#399

AGENTS.md

@@ -124,7 +124,7 @@ npm run preview
 - For arrays, never put whitespace or a line break immediately before `]`.
 - Keep the first element on the same line as `[` by default.
 - If an array would exceed the line limit, break after `[` and indent
-  elements 4 spaces deeper than the statement's base indentation.
+  elements by 4 spaces.
 
 ### Ruby delimiter and wrapping rules
 
@@ -140,32 +140,6 @@ npm run preview
   99 文字を超えるなら block 形式へ切り替へるか、message 定数化などで縮める。
 - Ruby の method chain や call argument を折り返す際、call-site の `)` を
   block close のやうに独立させない。
-- Ruby では、行末の `\` を用途を問はず一切使用しない。
-- Ruby では、文字列連結、logger message、method call、条件式、SQL 断片、
-  正規表現その他すべての式で、行末バックスラッシュによる継続を禁止する。
-- Ruby の block body は、その基準位置から 2 空白深くする。
-- Ruby の wrapped expression、method argument、array element、hash pair などの
-  continuation indentation は、その statement の基準位置から 4 空白深くする。
-- Ruby の continuation indentation を、行頭からの絶対空白数として扱はない。
-- Ruby では、暗黙的に継続可能な構文を優先し、method call、array、Hash 及び
-  括弧内ではバックスラッシュなしで改行する。
-- Ruby では、行長制限を守るために行末バックスラッシュを導入してはならない。
-- Ruby で行末バックスラッシュが必要に見える場合は、括弧内で自然に改行する、
-  一つの文字列補間へまとめる、中間変数へ分ける、`format` を使ふ、heredoc を
-  使ふ、array 又は Hash を組み立ててから処理する、条件式全体を括弧で囲む、
-  method へ抽出する、のいづれかへ書き換へる。
-- Ruby では、一つの文字列を、改行をまたいだ隣接文字列 literal として記述しない。
-- Ruby では、method argument 内でも、複数の文字列 literal を区切りなしで縦に
-  並べない。
-- RSpec の `describe`、`context`、`it` 等の description が長い場合は、意味を
-  保ったまま一行へ収まる文言へ短縮する。
-- 文字列を短縮できない場合は、用途に応じて `format`、heredoc 又は中間変数を
-  検討する。
-- ただし RSpec description では、原則として簡潔な一行の文字列を使ふ。
-- formatter 又は自動修正にも、Ruby の行末バックスラッシュを生成させない。
-- 新規 code だけでなく、今回触れる Ruby code にも行末バックスラッシュを残さない。
-- 例へば class body 内の array は、class body の 2 空白を基準に、更に 4 空白
-  深くするため、結果として行頭から 6 空白になる。
 
 Bad:
 
@@ -217,63 +191,6 @@ end
 
 Bad:
 
-```rb
-Rails.logger.info(
-    "post_import_metadata_fetch_failure "\
-    "#{ payload.to_json }")
-```
-
-Good:
-
-```rb
-payload = {
-    error: e.class.name,
-    message: e.message }
-
-Rails.logger.info(
-    "post_import_metadata_fetch_failure #{ payload.to_json }")
-```
-
-Bad:
-
-```rb
-message = "first "\
-          "second"
-```
-
-Good:
-
-```rb
-message = format(
-    '%<first>s %<second>s',
-    first: 'first',
-    second: 'second')
-```
-
-Bad:
-
-```rb
-result = first_value + \
-         second_value
-```
-
-Bad:
-
-```rb
-it(
-    'returns 409 when stale changes '
-    'do not conflict'
-) do
-```
-
-Good:
-
-```rb
-it 'returns mergeable 409 for stale non-conflicting changes' do
-```
-
-Bad:
-
 ```rb
 records.each {
   do_work(_1) }
@@ -308,37 +225,20 @@ records.each {
   formatting as the local reference shape: component and callback bodies use
   2-space block indentation, single-line bodies do not gain unnecessary
   braces, wrapped expressions use 4-space continuation indentation, multi-
-  stage ternaries use explicit parentheses, and TypeScript / TSX indentation
-  and alignment whitespace compress every complete run of 8 spaces to tabs.
+  stage ternaries use explicit parentheses, and only complete leading runs
+  of 8 spaces are compressed to tabs.
+- In TypeScript and TSX only, tabs are for leading 8-column compression only.
 - A tab does not represent one indentation level.
-- In TypeScript and TSX, first determine visible indentation using 2-space
-  block indentation and 4-space continuation indentation, then compress every
-  complete run of 8 spaces used for indentation or column alignment to tabs.
-- In TypeScript and TSX, 8-space compression is mandatory, not optional.
-- In TypeScript and TSX, this applies both to leading indentation and to
-  alignment whitespace after non-space text, such as aligned inline type
-  columns.
-- In TypeScript and TSX, keep residual 2, 4, or 6 spaces after each tab
-  compression.
-- In TypeScript and TSX, do not treat a tab as one logical indentation level.
-- In TypeScript and TSX, do not alter string literals, template-literal
-  contents, regular expressions, or user-facing text merely to apply tab
-  compression.
+- Do not replace 2-space or 4-space indentation with tabs.
+- First determine visible indentation using 2-space block indentation and
+  4-space continuation indentation, then compress only complete leading runs
+  of 8 spaces into tabs.
+- Tabs are only for leading indentation, never for spaces after non-space
+  text.
+- Keep residual leading 2, 4, or 6 spaces after any tab compression.
 - Examples: 2 columns = 2 spaces, 4 columns = 4 spaces, 6 columns = 6
   spaces, 8 columns = 1 tab, 10 columns = 1 tab + 2 spaces, 12 columns = 1
-  tab + 4 spaces, 14 columns = 1 tab + 6 spaces, 16 columns = 2 tabs.
-- When TypeScript or TSX code already uses column alignment, apply the same
-  8-space compression rule to that alignment whitespace.
-- Example:
-
-```ts
-type Props = {
-    row:	      PostImportRow
-    displayNumber?:   number
-    onEdit?:	  () => void
-    onRetry?:	  () => void
-    onToggleSkip?:    (checked: boolean) => void }
-```
+  tab + 4 spaces, 16 columns = 2 tabs.
 - TypeScript and TSX imports may stay on one line if they remain within the
   line limit; do not expand short type-only imports mechanically.
 - Keep runtime value imports and type imports in separate declarations.
@@ -574,32 +474,8 @@ and layout reuse, follow `frontend/AGENTS.md`.
   wording and placement before implementing it.
 - Do not invent replacement copy when removing unrequested wording.
 - Do not create, modify, or run tests unless the user explicitly asks for
-  test work. When the user asks for tests, keep working within the permitted
-  test-file scope and rerun them until they pass or the remaining failure is
-  clearly blocked.
-- Test-only work includes adding, updating, deleting, reorganising, or fixing
-  SyntaxError in tests. During test-only work, do not modify production code.
-- During test-only work, do not change production constants, behaviour, API
-  contracts, validation, routes, authentication, permissions, UI, copy,
-  dependencies, limits, thresholds, defaults, migrations, schema, or
-  environment settings to satisfy tests.
-- Do not make production code match failing tests, mock assumptions, fixtures,
-  snapshots, old expectations, or stale setup. This includes changing
-  production constants merely because a test expects a different value.
-- If test work reveals a production bug, spec mismatch, or missing behaviour,
-  stop without modifying production code and report: the failing test or
-  discovered issue, the related production file, the actual behaviour, the
-  expected behaviour, and why a production change appears necessary.
-- Modify production code for test failures only when the user explicitly asks
-  for that production change. Do not expand a test task into a production task
-  on your own authority.
-- If the user explicitly asks for both production implementation and test
-  updates, implement production code to the confirmed specification first,
-  then add or update tests to verify that specification. Never roll production
-  behaviour back to satisfy old tests.
-- If it is unclear whether the test or the production implementation is stale,
-  or a test cannot be corrected without changing production code, ask the user
-  instead of guessing.
+  test work. When the user asks for tests, keep working and rerun them until
+  they pass or the remaining failure is clearly blocked.
 
 ## Backend rules
 
@@ -722,10 +598,10 @@ and layout reuse, follow `frontend/AGENTS.md`.
   beginning of a line.
 - The TSX-specific self-review must confirm JSX closing markers and closing
   parentheses keep the surrounding compact style.
-- The TypeScript/TSX self-review must confirm block indentation uses 2 spaces
-  per level, wrapped continuations use the repository's 4-space continuation
-  alignment, and every complete run of 8 spaces used for indentation or
-  alignment has been compressed to tabs.
+- The TypeScript/TSX self-review must confirm leading block indentation uses
+  2 spaces per level, wrapped continuations use the repository's 4-space
+  continuation alignment, and complete leading runs of 8 spaces may be
+  compressed to tabs.
 - Prefer `const` arrow functions for TypeScript/TSX component and helper declarations.
 - Put two blank lines before and after top-level `const` function
   declarations, unless imports, exports, or file boundaries make that awkward.
@@ -738,18 +614,9 @@ and layout reuse, follow `frontend/AGENTS.md`.
 - Indent the block body 2 spaces deeper than the keyword and opening brace.
 - Put the closing `}` on its own line at the same indentation as the keyword.
 - Do not write `try {`, `catch {`, or `finally {`.
-- In TypeScript and TSX, convert every complete run of 8 spaces used for
-  indentation or alignment to a tab character.
-- In TypeScript and TSX, a tab is exactly equivalent to 8 columns, whether it
-  appears at the beginning of a line or in alignment whitespace after
-  non-space text.
-- In TSX, JSX nesting uses 2-space block indentation and wrapped JSX
-  attributes use 4-space continuation indentation; after visible columns are
-  determined, compress every complete run of 8 spaces in the resulting
-  indentation or alignment to tabs.
-- In TSX, do not leave JSX subtree indentation at 8, 10, 12, 14, or 16
-  columns as spaces alone; convert each complete run of 8 spaces to tabs and
-  keep only the residual 2, 4, or 6 spaces.
+- In TypeScript and TSX, convert every complete leading run of 8 spaces to a
+  tab character.
+- A leading tab is exactly equivalent to 8 leading spaces.
 - In TypeScript and TSX function declarations, including `const` arrow
   function declarations, classify the parameter list before placing the closing
   `)`.
@@ -1392,9 +1259,9 @@ to `.ts` and `.tsx`:
 7. JSX `>` and `/>` stay with the final prop unless nearby code proves
    otherwise.
 8. JSX closing parentheses keep the compact local style.
-9. Block indentation uses 2 spaces per level, wrapped continuations use the
-   repository's 4-space continuation alignment, and every complete run of 8
-   spaces used for indentation or alignment has been compressed to tabs.
+9. Leading block indentation uses 2 spaces per level, wrapped continuations
+   use the repository's 4-space continuation alignment, and complete leading
+   runs of 8 spaces may be compressed to tabs.
 10. No line has trailing whitespace.
 
 Preferred:

backend/app/controllers/posts_controller.rb

@@ -131,7 +131,6 @@ class PostsController < ApplicationController
           title: nil,
           thumbnail_base: nil,
           tags: nil,
-          display_tags: [],
           original_created_from: nil,
           original_created_before: nil,
           duration: nil,
@@ -154,7 +153,6 @@ class PostsController < ApplicationController
         title: metadata[:title],
         thumbnail_base: metadata[:thumbnail_base],
         tags: metadata[:tags],
-        display_tags: metadata[:display_tags],
         original_created_from: metadata[:original_created_from],
         original_created_before: metadata[:original_created_before],
         duration: metadata[:duration],
@@ -175,7 +173,6 @@ class PostsController < ApplicationController
         title: nil,
         thumbnail_base: nil,
         tags: nil,
-        display_tags: [],
         original_created_from: nil,
         original_created_before: nil,
         duration: nil,
@@ -216,8 +213,7 @@ class PostsController < ApplicationController
 
     preflight = PostCreatePreflight.new(
         attributes: post_create_attributes,
-        thumbnail: params[:thumbnail],
-        host: request.base_url).run
+        thumbnail: params[:thumbnail]).run
     return render json: dry_run_json(preflight) if bool?(:dry)
     if preflight[:existing_post_id].present?
       post = Post.new(url: preflight[:url])
@@ -274,11 +270,7 @@ class PostsController < ApplicationController
     return head :payload_too_large if request.content_length.to_i > MAX_BULK_REQUEST_BYTES
     posts = parse_bulk_posts_manifest
     thumbnails = parse_bulk_thumbnails(posts.length)
-    result = PostBulkCreator.new(
-        actor: current_user,
-        posts:,
-        thumbnails:,
-        host: request.base_url).run
+    result = PostBulkCreator.new(actor: current_user, posts:, thumbnails:).run
     render json: result
   rescue JSON::ParserError
     render_bad_request 'posts manifest の JSON が不正です．'
@@ -632,7 +624,7 @@ class PostsController < ApplicationController
     return nil if post_id.blank?
 
     post = Post.with_attached_thumbnail.find_by(id: post_id)
-    PostCompactRepr.base(post, host: request.base_url)
+    PostCompactRepr.base(post)
   end
 
   def dry_run_json preflight
@@ -641,7 +633,6 @@ class PostsController < ApplicationController
         :title,
         :thumbnail_base,
         :tags,
-        :display_tags,
         :parent_post_ids,
         :original_created_from,
         :original_created_before,
@@ -732,7 +723,6 @@ class PostsController < ApplicationController
 
   def post_incoming_snapshot title:, original_created_from:, original_created_before:,
                              tag_names:, video_ms_param:, duration_param:, parent_post_ids:
-    validate_original_created_values!(original_created_from, original_created_before)
     Tag.normalise_tags!(tag_names, with_tagme: false, deny_deprecated: true,
                                         with_sections: true) =>
         { tags:, sections: }
@@ -770,23 +760,6 @@ class PostsController < ApplicationController
     value.to_s
   end
 
-  def validate_original_created_values! original_created_from, original_created_before
-    candidate = Post.new(
-        url: 'https://example.invalid/original-created-validation',
-        original_created_from:,
-        original_created_before:)
-    candidate.valid?
-    fields = [:original_created_from, :original_created_before, :original_created_at]
-    relevant_errors = candidate.errors.select { fields.include?(_1.attribute) }
-    return if relevant_errors.empty?
-
-    invalid_post = Post.new
-    relevant_errors.each { |error|
-      invalid_post.errors.add(error.attribute, error.message)
-    }
-    raise ActiveRecord::RecordInvalid, invalid_post
-  end
-
   def section_literal section
     "[#{ Post.ms_to_time(section[0]) }-#{ section[1] ? Post.ms_to_time(section[1]) : '' }]"
   end

backend/app/controllers/preview_controller.rb

@@ -18,12 +18,14 @@ class PreviewController < ApplicationController
   def thumbnail
     return render_bad_request('URL は必須です．') if params[:url].blank?
 
-    attachment =
-        Post.resized_thumbnail_attachment(
-            StringIO.new(Preview::ThumbnailFetcher.fetch(params[:url])))
-    send_data attachment[:io].read,
-              type: attachment[:content_type],
-              disposition: 'inline'
+    image = MiniMagick::Image.read(Preview::ThumbnailFetcher.fetch(params[:url]))
+    image.auto_orient
+    image.resize '180x180>'
+    image.format 'png'
+    width, height = image.dimensions
+    raise Preview::ThumbnailFetcher::GenerationFailed, 'サムネール画像の変換に失敗しました．' if width > 180 || height > 180
+
+    send_data image.to_blob, type: 'image/png', disposition: 'inline'
   rescue Preview::UrlSafety::UnsafeUrl => e
     render_bad_request(e.message)
   rescue Preview::HttpFetcher::FetchTimeout => e

backend/app/models/post.rb

@@ -17,12 +17,12 @@ class Post < ApplicationRecord
   MAX_SVG_DIMENSION = 4_096
   MAX_SVG_PIXELS = 16_777_216
   THUMBNAIL_PROCESS_TIMEOUT = 5.seconds
+
   def self.resized_thumbnail_attachment(upload, content_type: nil)
     upload.rewind
     bytes = upload.read
     blob = Timeout.timeout(THUMBNAIL_PROCESS_TIMEOUT) do
       image = image_for_thumbnail_upload(bytes, content_type:)
-      image.auto_orient
       image.resize '180x180'
       image.format 'jpg'
       image.to_blob
@@ -138,10 +138,7 @@ class Post < ApplicationRecord
   end
 
   def self.section_literal section
-    end_ms =
-        section.end_ms ? Post.ms_to_time(section.end_ms) : ''
-
-    "[#{ Post.ms_to_time(section.begin_ms) }-#{ end_ms }]"
+    "[#{ Post.ms_to_time(section.begin_ms) }-#{ section.end_ms ? Post.ms_to_time(section.end_ms) : '' }]"
   end
 
   def self.ms_to_time ms
@@ -228,23 +225,9 @@ class Post < ApplicationRecord
   end
 
   def self.image_for_thumbnail_upload(bytes, content_type: nil)
-    if svg_content_type?(content_type) || svg_document_bytes?(bytes)
-      return decode_svg_thumbnail(bytes)
-    end
+    return decode_raster_thumbnail(bytes) unless svg_content_type?(content_type) || svg_document_bytes?(bytes)
 
-    raise MiniMagick::Error, 'サムネイル画像の形式が不正です．' unless raster_thumbnail_bytes?(bytes)
-
-    decode_raster_thumbnail(bytes)
-  end
-
-  def self.raster_thumbnail_bytes?(bytes)
-    raster_thumbnail_format(bytes).present?
-  end
-
-  def self.remote_thumbnail_image_bytes?(bytes, content_type: nil)
-    return true if svg_content_type?(content_type) || svg_document_bytes?(bytes)
-
-    raster_thumbnail_bytes?(bytes)
+    decode_svg_thumbnail(bytes)
   end
 
   def self.svg_content_type?(content_type)
@@ -271,18 +254,6 @@ class Post < ApplicationRecord
     MiniMagick::Image.read(sanitised_svg_bytes(bytes))
   end
 
-  def self.raster_thumbnail_format(bytes)
-    binary = bytes.to_s.b
-    return 'jpeg' if binary.start_with?("\xFF\xD8\xFF".b)
-    return 'png' if binary.start_with?("\x89PNG\r\n\x1A\n".b)
-    return 'gif' if binary.start_with?('GIF87a'.b) || binary.start_with?('GIF89a'.b)
-    return 'webp' if binary.bytesize >= 12 &&
-                     binary.start_with?('RIFF'.b) &&
-                     binary.byteslice(8, 4) == 'WEBP'
-
-    nil
-  end
-
   def self.sanitised_svg_bytes(bytes)
     parse_options =
         Nokogiri::XML::ParseOptions::STRICT |
@@ -326,9 +297,7 @@ class Post < ApplicationRecord
   end
 
   def self.external_svg_reference?(attribute_name, attribute_value)
-    if ['href', 'xlink:href', 'src'].include?(attribute_name)
-      return external_svg_url?(attribute_value)
-    end
+    return external_svg_url?(attribute_value) if ['href', 'xlink:href', 'src'].include?(attribute_name)
     return style_contains_disallowed_urls?(attribute_value) if attribute_name == 'style'
     return svg_url_function_disallowed?(attribute_value) if attribute_value.match?(/url\s*\(/i)
 
@@ -349,12 +318,7 @@ class Post < ApplicationRecord
 
   def self.svg_url_function_disallowed?(value)
     value.to_s.scan(/url\s*\(([^)]*)\)/i).flatten.any? do |entry|
-      reference =
-          entry.to_s.strip
-               .delete_prefix("'")
-               .delete_prefix('"')
-               .delete_suffix("'")
-               .delete_suffix('"')
+      reference = entry.to_s.strip.delete_prefix("'").delete_prefix('"').delete_suffix("'").delete_suffix('"')
       reference.present? && !(reference.start_with?('#'))
     end
   end
@@ -390,7 +354,6 @@ class Post < ApplicationRecord
                        :svg_content_type?,
                        :decode_raster_thumbnail,
                        :decode_svg_thumbnail,
-                       :raster_thumbnail_format,
                        :sanitised_svg_bytes,
                        :svg_uses_disallowed_features?,
                        :external_svg_reference?,
@@ -443,12 +406,7 @@ class Post < ApplicationRecord
 
     match =
         value.match(
-            /
-              \A(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})
-              (?::(\d{2})(?:\.(\d+))?)?
-              (Z|[+-]\d{2}:?\d{2})?
-              \z
-            /x)
+            /\A(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})(?::(\d{2})(?:\.(\d+))?)?(Z|[+-]\d{2}:?\d{2})?\z/)
     return nil if match.nil?
 
     year = match[1].to_i

backend/app/representations/post_compact_repr.rb

@@ -4,16 +4,23 @@
 module PostCompactRepr
   module_function
 
-  def base post, host: nil
+  def base post
     return nil if post.nil?
 
-    PostRepr
-        .common(post, host:)
-        .slice(
-            'id',
-            'title',
-            'url',
-            'thumbnail',
-            'thumbnail_base')
+    {
+        id: post.id,
+        title: post.title,
+        url: post.url,
+        thumbnail_url: thumbnail_url(post) }
+  end
+
+  def thumbnail_url post
+    return nil unless post.thumbnail.attached?
+
+    Rails.application.routes.url_helpers.rails_storage_proxy_url(
+        post.thumbnail,
+        only_path: false)
+  rescue ActionController::UrlGenerationError, ArgumentError, URI::InvalidURIError
+    nil
   end
 end

backend/app/representations/post_repr.rb

@@ -17,13 +17,8 @@ module PostRepr
 
   module_function
 
-  def base post, current_user = nil, host: nil
-    json =
-        if host.present?
-          common(post, host:)
-        else
-          common(post)
-        end
+  def base post, current_user = nil
+    json = common(post)
     json['tags'] = tag_json(post)
     json['uploaded_user'] = post.uploaded_user && UserRepr.base(post.uploaded_user)
     json['viewed'] = current_user ? current_user.viewed?(post) : false
@@ -31,59 +26,31 @@ module PostRepr
   end
 
   def detail post, current_user = nil, parent_posts: [], child_posts: [],
-             sibling_posts: { }, related: [], host: nil
-    if host.present?
-      base(post, current_user, host:).merge(
-          'parent_posts' => cards(parent_posts, host:),
-          'child_posts' => cards(child_posts, host:),
-          'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
-            cards(posts, host:)
-          },
-          'related' => cards(related, host:))
-    else
-      base(post, current_user).merge(
-          'parent_posts' => cards(parent_posts),
-          'child_posts' => cards(child_posts),
-          'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
-            cards(posts)
-          },
-          'related' => cards(related))
-    end
+             sibling_posts: { }, related: []
+    base(post, current_user).merge(
+        'parent_posts' => cards(parent_posts),
+        'child_posts' => cards(child_posts),
+        'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
+          cards(posts)
+        },
+        'related' => cards(related))
   end
 
-  def card post, host: nil
-    if host.present?
-      common(post, host:).merge('parent_posts' => [], 'child_posts' => [])
-    else
-      common(post).merge('parent_posts' => [], 'child_posts' => [])
-    end
+  def card post
+    common(post).merge('parent_posts' => [], 'child_posts' => [])
   end
 
-  def cards posts, host: nil
-    if host.present?
-      posts.map { |post| card(post, host:) }
-    else
-      posts.map { |post| card(post) }
-    end
+  def cards posts
+    posts.map { |post| card(post) }
   end
 
-  def many posts, current_user = nil, host: nil
-    if host.present?
-      posts.map { |p| base(p, current_user, host:) }
-    else
-      posts.map { |p| base(p, current_user) }
-    end
+  def many posts, current_user = nil
+    posts.map { |p| base(p, current_user) }
   end
 
-  def common post, host: nil
+  def common post
     BASE_FIELDS.to_h { |field| [field.to_s, post.public_send(field)] }
-               .merge(
-                   'thumbnail' =>
-                       if host.present?
-                         thumbnail_url(post, host:)
-                       else
-                         thumbnail_url(post)
-                       end)
+               .merge('thumbnail' => thumbnail_url(post))
   end
 
   def tag_json post
@@ -98,22 +65,11 @@ module PostRepr
     }
   end
 
-  def thumbnail_url post, host: nil
+  def thumbnail_url post
     return nil unless post.thumbnail.attached?
 
-    options = { only_path: false }
-    options[:host] = host if host.present?
-
-    Rails.application.routes.url_helpers.rails_storage_proxy_url(post.thumbnail, **options)
-  rescue ActionController::UrlGenerationError, ArgumentError, URI::InvalidURIError => e
-    payload = {
-        post_id: post.id,
-        attachment_id: post.thumbnail.attachment&.id,
-        blob_id: post.thumbnail.blob&.id,
-        error_class: e.class,
-        message: e.message }
-
-    Rails.logger.warn("PostRepr.thumbnail_url failed #{ payload.to_json }")
+    Rails.application.routes.url_helpers.rails_blob_url(post.thumbnail, only_path: false)
+  rescue
     nil
   end
 end

backend/app/services/post_bulk_creator.rb

@@ -1,9 +1,8 @@
 class PostBulkCreator
-  def initialize actor:, posts:, thumbnails:, host: nil
+  def initialize actor:, posts:, thumbnails:
     @actor_id = actor.id
     @posts = posts
     @thumbnails = thumbnails
-    @host = host
   end
 
   def run
@@ -65,8 +64,7 @@ class PostBulkCreator
     preflight =
         PostCreatePreflight.new(
             attributes: attributes,
-            thumbnail: thumbnail_for(index, attributes),
-            host: @host).run
+            thumbnail: thumbnail_for(index, attributes)).run
     if preflight[:existing_post_id].present?
       return {
           status: 'skipped',
@@ -197,6 +195,6 @@ class PostBulkCreator
   end
 
   def compact_existing_post post
-    PostCompactRepr.base(post, host: @host)
+    PostCompactRepr.base(post)
   end
 end

backend/app/services/post_create_plan.rb

@@ -12,8 +12,6 @@ class PostCreatePlan
     direct_tag_specs, tag_sections = parse_direct_tag_specs
     default_tag_specs = build_default_tag_specs(direct_tag_specs)
     snapshot_tag_specs = merge_tag_specs(direct_tag_specs + default_tag_specs)
-    preload_existing_tags_by_name!(snapshot_tag_specs.map { _1[:name] })
-    validate_new_tag_specs!(snapshot_tag_specs)
     post_tag_specs = expand_parent_tag_specs(snapshot_tag_specs)
     video_ms = normalise_video_ms(snapshot_tag_specs)
     validate_video_sections!(video_ms, tag_sections)
@@ -27,7 +25,6 @@ class PostCreatePlan
         original_created_from: @attributes[:original_created_from].presence,
         original_created_before: @attributes[:original_created_before].presence,
         tags: serialised_tags(direct_tag_specs, tag_sections),
-        display_tags: display_tags(direct_tag_specs, tag_sections),
         duration: @attributes[:duration].to_s,
         video_ms: video_ms,
         parent_post_ids: parent_post_ids.join(' '),
@@ -85,11 +82,9 @@ class PostCreatePlan
           end_raw: match[3],
           tag_name: name)
     end
-    if name.include?('[') || name.include?(']')
-      raise Tag::SectionLiteralParseError.new(raw_name, raw_name)
-    end
+    raise Tag::SectionLiteralParseError.new(raw_name, raw_name) if name.include?('[') || name.include?(']')
 
-    [resolved_tag_name(name), category&.to_sym, sections]
+    [TagName.canonicalise(name).first, category&.to_sym, sections]
   end
 
   def build_default_tag_specs direct_tag_specs
@@ -108,31 +103,6 @@ class PostCreatePlan
     default_tag_specs
   end
 
-  def validate_new_tag_specs! specs
-    Array(specs).each do |spec|
-      next if existing_tags_by_name.key?(spec[:name])
-
-      validate_new_tag_spec!(spec)
-    end
-  end
-
-  def validate_new_tag_spec! spec
-    tag_name = TagName.new(name: spec[:name])
-    tag = Tag.new(category: spec[:category], tag_name:)
-    return if tag_name.valid? && tag.valid?
-
-    post = Post.new
-    tag_name.errors[:name].each do |message|
-      post.errors.add :tags, "#{ spec[:name] }: #{ message }"
-    end
-    tag.errors.each do |error|
-      next if error.attribute == :tag_name
-
-      post.errors.add :tags, "#{ spec[:name] }: #{ error.message }"
-    end
-    raise ActiveRecord::RecordInvalid, post
-  end
-
   def expand_parent_tag_specs snapshot_tag_specs
     existing_snapshot_tags = snapshot_tag_specs.filter_map { existing_tags_by_name[_1[:name]] }
     expanded_parent_specs =
@@ -165,17 +135,6 @@ class PostCreatePlan
     end
   end
 
-  def preload_existing_tags_by_name! names
-    wanted_names = Array(names).map { _1.to_s }.reject(&:blank?).uniq
-    missing_names = wanted_names - existing_tags_by_name.keys
-    return if missing_names.empty?
-
-    existing_tags_by_name.merge!(
-        Tag.joins(:tag_name)
-           .where(tag_names: { name: missing_names })
-           .index_by(&:name))
-  end
-
   def canonical_tag_name_without_sections raw_name
     name, = parse_raw_tag_name(raw_name)
     name
@@ -203,24 +162,10 @@ class PostCreatePlan
 
   def serialised_tags direct_tag_specs, tag_sections
     direct_tag_specs.map { |spec|
-      "#{ spec[:name] }#{ tag_sections[spec[:name]].to_a.map { section_literal(_1) }.join }"
+      "#{ spec[:name] }#{ tag_sections[spec[:name]].to_a.map { Post.section_literal(_1) }.join }"
     }.sort.join(' ')
   end
 
-  def display_tags direct_tag_specs, tag_sections
-    direct_tag_specs.map { |spec|
-      {
-          name: spec[:name],
-          category: spec[:category].to_s,
-          section_literals: tag_sections[spec[:name]].to_a.map { section_literal(_1) } }
-    }.sort_by { _1[:name] }
-  end
-
-  def section_literal range
-    begin_ms, end_ms = range
-    "[#{ Post.ms_to_time(begin_ms) }-#{ end_ms ? Post.ms_to_time(end_ms) : '' }]"
-  end
-
   def normalise_video_ms snapshot_tag_specs
     return nil unless snapshot_tag_specs.any? { _1[:name] == VIDEO_TAG_NAME }
 
@@ -261,11 +206,4 @@ class PostCreatePlan
       end
     end
   end
-
-  def resolved_tag_name name
-    tag_name = TagName.includes(:canonical).find_by(name:)
-    return name if tag_name.nil?
-
-    (tag_name.canonical || tag_name).name
-  end
 end

backend/app/services/post_create_preflight.rb

@@ -9,10 +9,9 @@ class PostCreatePreflight
     end
   end
 
-  def initialize attributes:, thumbnail: nil, host: nil
+  def initialize attributes:, thumbnail: nil
     @attributes = attributes.symbolize_keys
     @thumbnail = thumbnail
-    @host = host
   end
 
   def run
@@ -30,7 +29,6 @@ class PostCreatePreflight
           original_created_before: preview[:attributes]['original_created_before'],
           duration: preview[:attributes]['duration'],
           video_ms: preview[:attributes]['video_ms'],
-          display_tags: preview[:display_tags] || [],
           field_warnings: final_field_warnings(preview[:field_warnings] || { }),
           base_warnings: preview[:base_warnings],
           existing_post_id: preview[:existing_post_id],
@@ -65,7 +63,6 @@ class PostCreatePreflight
         original_created_before: plan[:original_created_before],
         duration: plan[:duration],
         video_ms: plan[:video_ms],
-        display_tags: plan[:display_tags],
         direct_tag_specs: plan[:direct_tag_specs],
         default_tag_specs: plan[:default_tag_specs],
         snapshot_tag_specs: plan[:snapshot_tag_specs],
@@ -125,7 +122,7 @@ class PostCreatePreflight
     return nil if post_id.blank?
 
     post = Post.with_attached_thumbnail.find_by(id: post_id)
-    PostCompactRepr.base(post, host: @host)
+    PostCompactRepr.base(post)
   end
 
   def final_field_warnings field_warnings

backend/app/services/post_import_previewer.rb

@@ -3,14 +3,14 @@ require 'timeout'
 
 class PostImportPreviewer
   FIELDS = [
-      'title',
-      'thumbnail_base',
-      'original_created_from',
-      'original_created_before',
-      'video_ms',
-      'duration',
-      'tags',
-      'parent_post_ids'].freeze
+    'title',
+    'thumbnail_base',
+    'original_created_from',
+    'original_created_before',
+    'video_ms',
+    'duration',
+    'tags',
+    'parent_post_ids'].freeze
   FETCH_WARNING_FIELDS = ['url', 'title', 'thumbnail_base'].freeze
   TITLE_FETCH_WARNING = 'タイトルを取得できませんでした．'.freeze
   THUMBNAIL_FETCH_WARNING = 'サムネールを取得できませんでした．'.freeze
@@ -126,6 +126,7 @@ class PostImportPreviewer
     validate_basic_data(attributes, validation_errors)
     validate_preview_tags(merged_tags(tag_sources, provenance['tags']),
                           validation_errors,
+                          field_warnings,
                           known_tags)
     validate_parents(attributes['parent_post_ids'], validation_errors, existing_parent_ids)
     attributes.delete('url')
@@ -225,15 +226,15 @@ class PostImportPreviewer
     end
     { data:, warnings:, validation_errors: { } }
   rescue Preview::UrlSafety::UnsafeUrl => e
-    payload = { error: e.class.name, message: e.message }
     Rails.logger.info(
-        "post_import_metadata_fetch_unsafe_url #{ payload.to_json }")
+        "post_import_metadata_fetch_unsafe_url "\
+        "#{ { error: e.class.name, message: e.message }.to_json }")
     { data: { }, warnings: { }, validation_errors: { url: [e.message] } }
   rescue Preview::HttpFetcher::FetchFailed,
          Preview::HttpFetcher::ResponseTooLarge => e
-    payload = { error: e.class.name, message: e.message }
     Rails.logger.info(
-        "post_import_metadata_fetch_failure #{ payload.to_json }")
+        "post_import_metadata_fetch_failure "\
+        "#{ { error: e.class.name, message: e.message }.to_json }")
     { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] }, validation_errors: { } }
   end
 
@@ -335,14 +336,14 @@ class PostImportPreviewer
   def safe_fetch_metadata url
     fetch_metadata(url)
   rescue Preview::UrlSafety::UnsafeUrl => e
-    payload = { error: e.class.name, message: e.message }
     Rails.logger.info(
-        "post_import_metadata_fetch_unsafe_url #{ payload.to_json }")
+        "post_import_metadata_fetch_unsafe_url "\
+        "#{ { error: e.class.name, message: e.message }.to_json }")
     { data: { }, warnings: { }, validation_errors: { url: [e.message] } }
   rescue StandardError => e
-    payload = { error: e.class.name, message: e.message }
     Rails.logger.error(
-        "post_import_metadata_fetch_unexpected_failure #{ payload.to_json }")
+        "post_import_metadata_fetch_unexpected_failure "\
+        "#{ { error: e.class.name, message: e.message }.to_json }")
     { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] }, validation_errors: { } }
   end
 
@@ -449,7 +450,7 @@ class PostImportPreviewer
     []
   end
 
-  def validate_preview_tags raw, errors, known_tags
+  def validate_preview_tags raw, errors, field_warnings, known_tags
     names = raw.to_s.split
     return if names.empty?
     if names.any? { _1.downcase.start_with?('nico:') }
@@ -461,6 +462,11 @@ class PostImportPreviewer
     existing = parsed.filter_map { known_tags[_1] }
     deprecated = existing.select(&:deprecated?).map(&:name)
     errors[:tags] = ["廃止済みタグがあります: #{ deprecated.join(' ') }"] if deprecated.present?
+    known = existing.reject(&:deprecated?).map(&:name)
+    new_tags = parsed.uniq - known
+    if new_tags.present?
+      add_field_warning!(field_warnings, 'tags', "新規タグを作成します: #{ new_tags.join(' ') }")
+    end
   rescue Tag::SectionLiteralParseError
     errors[:tags] = ['タグ区間の記法が不正です．']
   end

backend/app/services/post_metadata_fetcher.rb

@@ -3,9 +3,10 @@ require 'date'
 
 class PostMetadataFetcher
   TIMESTAMP_PATTERN =
-      /\A(\d{4})-(\d{2})-(\d{2})T(\d{2})
-        (?::(\d{2})(?::(\d{2})(?:\.(\d+))?)?)?
-        (Z|[+-]\d{2}:?\d{2})?\z/x
+      Regexp.new(
+          '\A(\d{4})-(\d{2})-(\d{2})T(\d{2})' \
+          '(?::(\d{2})(?::(\d{2})(?:\.(\d+))?)?)?' \
+          '(Z|[+-]\d{2}:?\d{2})?\z')
 
   def self.fetch raw_url
     uri, = Preview::UrlSafety.validate(raw_url)
@@ -31,7 +32,6 @@ class PostMetadataFetcher
       original_created_from: serialise_time(created_range&.first),
       original_created_before: serialise_time(created_range&.last),
       duration: serialise_duration(duration),
-      display_tags: display_tags(platform_tags),
       tags: platform_tags.join(' ') }
   end
 
@@ -42,24 +42,6 @@ class PostMetadataFetcher
     []
   end
 
-  def self.display_tags names
-    return [] if names.blank?
-
-    existing_tags =
-        Tag
-        .joins(:tag_name)
-        .where(tag_names: { name: names })
-        .index_by(&:name)
-
-    names.map { |name|
-      tag = existing_tags[name]
-      {
-          name: name,
-          category: (tag&.category || 'meta'),
-          section_literals: [] }
-    }
-  end
-
   def self.original_created_range value
     return nil if value.blank?
 
@@ -186,7 +168,6 @@ class PostMetadataFetcher
   end
 
   private_class_method :platform_tags,
-                       :display_tags,
                        :original_created_range,
                        :parse_timestamp_range,
                        :parse_nanoseconds,

backend/app/services/post_thumbnail_upload_validator.rb

@@ -11,15 +11,10 @@ class PostThumbnailUploadValidator
     end
     raise InvalidUpload, 'thumbnail file size が大きすぎます．' if thumbnail.size > MAX_THUMBNAIL_BYTES
     raise InvalidUpload, 'サムネイル画像の形式が不正です．' unless allowed_content_type?(thumbnail.content_type)
-    bytes = thumbnail.read
-    raise InvalidUpload, 'サムネイル画像の形式が不正です．' if Post.svg_document_bytes?(bytes)
-    unless Post.raster_thumbnail_bytes?(bytes)
-      raise InvalidUpload, 'サムネイル画像の形式が不正です．'
-    end
+    raise InvalidUpload, 'サムネイル画像の形式が不正です．' if Post.svg_document_bytes?(thumbnail.read)
+    thumbnail.rewind
 
-    attachment = Post.resized_thumbnail_attachment(
-        StringIO.new(bytes),
-        content_type: thumbnail.content_type)
+    attachment = Post.resized_thumbnail_attachment(thumbnail, content_type: thumbnail.content_type)
     attachment[:io].close if attachment[:io].respond_to?(:close)
   rescue MiniMagick::Error, Timeout::Error
     raise InvalidUpload, 'サムネイル画像の変換に失敗しました．'

backend/app/services/preview/thumbnail_fetcher.rb

@@ -4,6 +4,10 @@ module Preview
     RASTER_IMAGE_CONTENT_TYPES = [
       'image/jpeg', 'image/png', 'image/gif', 'image/webp'
     ].freeze
+    REMOTE_IMAGE_CONTENT_TYPES = [
+      *RASTER_IMAGE_CONTENT_TYPES,
+      'image/svg+xml'
+    ].freeze
     HTML_MAX_BYTES = 1.megabyte
     NICONICO_XML_MAX_BYTES = 256.kilobytes
 
@@ -28,9 +32,7 @@ module Preview
     def self.fetch_image_response(raw_url)
       uri, = UrlSafety.validate(raw_url)
       response = HttpFetcher.fetch(uri.to_s)
-      unless Post.remote_thumbnail_image_bytes?(
-                 response.body,
-                 content_type: response.content_type)
+      unless allowed_remote_image_content_type?(response.content_type) || Post.svg_document_bytes?(response.body)
         raise GenerationFailed, 'サムネール画像が見つかりませんでした．'
       end
 
@@ -53,9 +55,7 @@ module Preview
       return nil if url.blank?
 
       response = HttpFetcher.fetch(url)
-      return nil unless Post.remote_thumbnail_image_bytes?(
-                            response.body,
-                            content_type: response.content_type)
+      return nil unless allowed_remote_image_content_type?(response.content_type)
 
       response.body
     rescue HttpFetcher::FetchTimeout
@@ -96,7 +96,13 @@ module Preview
       nil
     end
 
+    def self.allowed_remote_image_content_type?(content_type)
+      mime_type = content_type.to_s.split(';', 2).first.downcase.strip
+      REMOTE_IMAGE_CONTENT_TYPES.include?(mime_type)
+    end
+
     private_class_method :fetch_image_or_nil, :fetch_image!,
-                         :niconico_thumbnail_url
+                         :niconico_thumbnail_url,
+                         :allowed_remote_image_content_type?
   end
 end

backend/config/environments/development.rb

@@ -1,4 +1,4 @@
-require 'active_support/core_ext/integer/time'
+require "active_support/core_ext/integer/time"
 
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
@@ -17,8 +17,8 @@ Rails.application.configure do
 
   # Enable/disable Action Controller caching. By default Action Controller caching is disabled.
   # Run rails dev:cache to toggle Action Controller caching.
-  if Rails.root.join('tmp/caching-dev.txt').exist?
-    config.public_file_server.headers = { 'cache-control' => "public, max-age=#{2.days.to_i}" }
+  if Rails.root.join("tmp/caching-dev.txt").exist?
+    config.public_file_server.headers = { "cache-control" => "public, max-age=#{2.days.to_i}" }
   else
     config.action_controller.perform_caching = false
   end
@@ -36,11 +36,7 @@ Rails.application.configure do
   config.action_mailer.perform_caching = false
 
   # Set localhost to be used by links generated in mailer templates.
-  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
-  Rails.application.routes.default_url_options.merge!(
-      host: 'localhost',
-      port: 3002,
-      protocol: 'http')
+  config.action_mailer.default_url_options = { host: "localhost", port: 3000 }
 
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log

backend/spec/models/post_spec.rb

@@ -110,7 +110,7 @@ RSpec.describe Post, type: :model do
     end
 
     describe '.resized_thumbnail_attachment' do
-      it 'fits a wide image within 180x180 without distorting it' do
+      it 'centre-crops a wide image to 180x180 without distorting it' do
         blob = image_blob(
             width: 360,
             height: 180,
@@ -123,13 +123,13 @@ RSpec.describe Post, type: :model do
         resized = described_class.resized_thumbnail_attachment(upload_for(blob))
         image = read_image(resized)
 
-        expect(image.dimensions).to eq([180, 90])
-        expect_red(colour_at(image, 0, 45))
-        expect_green(colour_at(image, 90, 45))
-        expect_red(colour_at(image, 179, 45))
+        expect(image.dimensions).to eq([180, 180])
+        expect_green(colour_at(image, 0, 90))
+        expect_green(colour_at(image, 90, 90))
+        expect_green(colour_at(image, 179, 90))
       end
 
-      it 'fits a tall image within 180x180 without distorting it' do
+      it 'centre-crops a tall image to 180x180 without distorting it' do
         blob = image_blob(
             width: 180,
             height: 360,
@@ -142,10 +142,10 @@ RSpec.describe Post, type: :model do
         resized = described_class.resized_thumbnail_attachment(upload_for(blob))
         image = read_image(resized)
 
-        expect(image.dimensions).to eq([90, 180])
-        expect_red(colour_at(image, 45, 0))
-        expect_green(colour_at(image, 45, 90))
-        expect_red(colour_at(image, 45, 179))
+        expect(image.dimensions).to eq([180, 180])
+        expect_green(colour_at(image, 90, 0))
+        expect_green(colour_at(image, 90, 90))
+        expect_green(colour_at(image, 90, 179))
       end
 
       it 'keeps a square image square without distortion' do
@@ -192,7 +192,7 @@ RSpec.describe Post, type: :model do
 
         expect(post.thumbnail).to be_attached
         image = read_image(post.thumbnail)
-        expect(image.dimensions).to eq([180, 135])
+        expect(image.dimensions).to eq([180, 180])
       end
 
       it 'does not attach anything when thumbnail conversion fails' do

backend/spec/requests/post_imports_spec.rb

@@ -0,0 +1,184 @@
+require 'rails_helper'
+
+RSpec.describe 'Post imports API', type: :request do
+  let(:member) { create(:user, :member) }
+
+  before do
+    allow(Preview::UrlSafety).to receive(:validate) do |url|
+      [URI.parse(url), ['8.8.8.8']]
+    end
+    allow(PostMetadataFetcher).to receive(:fetch).and_return(
+      title: 'fetched title',
+      thumbnail_base: nil,
+      tags: ''
+    )
+  end
+
+  describe 'POST /posts/import/preview' do
+    it 'requires a member' do
+      sign_out
+      post '/posts/import/preview', params: { source: 'https://example.com/post' }
+      expect(response).to have_http_status(:unauthorized)
+
+      sign_in_as(create(:user, :guest))
+      post '/posts/import/preview', params: { source: 'https://example.com/post' }
+      expect(response).to have_http_status(:forbidden)
+    end
+
+    it 'parses a URL list and returns preview rows' do
+      sign_in_as(member)
+
+      post '/posts/import/preview', params: {
+        source: " https://example.com/one \r\n\r\nhttps://example.com/two"
+      }
+
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('rows').map { _1.fetch('source_row') }).to eq([1, 3])
+      expect(json.fetch('rows').map { _1.fetch('url') }).to eq([
+        'https://example.com/one',
+        'https://example.com/two'
+      ])
+    end
+
+    it 'returns a safe 400 response for an invalid source' do
+      sign_in_as(member)
+
+      post '/posts/import/preview', params: { source: '' }
+
+      expect(response).to have_http_status(:bad_request)
+      expect(json.fetch('message')).to eq('URL を入力してください．')
+    end
+  end
+
+  describe 'POST /posts/import/validate' do
+    it 'accepts camel-case row properties and returns their warnings' do
+      sign_in_as(member)
+
+      post '/posts/import/validate', params: {
+        rows: [{
+          sourceRow: '1',
+          url: 'https://example.com/post',
+          metadataUrl: 'https://example.com/post',
+          attributes: { title: 'manual title' },
+          provenance: { url: 'manual', title: 'manual' },
+          tagSources: { automatic: '', manual: '' },
+          fieldWarnings: { title: ['old warning'] },
+          baseWarnings: ['base warning']
+        }],
+        changed_row: -1
+      }
+
+      expect(response).to have_http_status(:ok)
+      result = json.fetch('rows').first
+      expect(result.fetch('source_row')).to eq(1)
+      expect(result.fetch('tag_sources')).to eq('automatic' => '', 'manual' => '')
+      expect(result.fetch('field_warnings')).to eq('title' => ['old warning'])
+      expect(result.fetch('base_warnings')).to eq(['base warning'])
+    end
+
+    it 'rejects a non-array rows value with 400' do
+      sign_in_as(member)
+
+      post '/posts/import/validate', params: { rows: { sourceRow: 1 }, changed_row: -1 }
+
+      expect(response).to have_http_status(:bad_request)
+      expect(json.fetch('message')).to eq('取込行の形式が不正です．')
+    end
+
+    it 'returns original created datetime validation errors for minute precision' do
+      sign_in_as(member)
+
+      post '/posts/import/validate', params: {
+        rows: [{
+          sourceRow: 1,
+          url: 'https://example.com/post',
+          metadataUrl: 'https://example.com/post',
+          attributes: {
+            originalCreatedFrom: '2020-01-01T00:00:30Z',
+            originalCreatedBefore: '2020-01-01T00:01Z' },
+          provenance: {
+            url: 'manual',
+            originalCreatedFrom: 'manual',
+            originalCreatedBefore: 'manual' },
+          tagSources: { automatic: '', manual: '' }
+        }],
+        changed_row: -1
+      }
+
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('rows').first.fetch('validation_errors')).to include(
+        'original_created_from' => ['オリジナルの作成日時は分単位で入力してください．']
+      )
+      expect(json.fetch('rows').first.fetch('validation_errors'))
+          .not_to have_key('original_created_at')
+    end
+  end
+
+  describe 'POST /posts/import' do
+    it 'keeps the duration string contract through preview, validate, and import' do
+      sign_in_as(member)
+      allow(PostMetadataFetcher).to receive(:fetch).and_return(
+        title: 'fetched title',
+        thumbnail_base: nil,
+        duration: '2.5',
+        tags: '動画'
+      )
+
+      post '/posts/import/preview', params: {
+        source: 'https://example.com/video'
+      }
+      preview_row = json.fetch('rows').first
+      expect(preview_row.dig('attributes', 'duration')).to eq('2.5')
+
+      post '/posts/import/validate', params: {
+        rows: [{
+          sourceRow: preview_row.fetch('source_row'),
+          url: preview_row.fetch('url'),
+          attributes: preview_row.fetch('attributes'),
+          provenance: preview_row.fetch('provenance'),
+          tagSources: preview_row.fetch('tag_sources'),
+          metadataUrl: preview_row.fetch('metadata_url')
+        }],
+        changed_row: -1
+      }
+      validated_row = json.fetch('rows').first
+      expect(validated_row.dig('attributes', 'duration')).to eq('2.5')
+
+      post '/posts/import', params: {
+        rows: [{
+          sourceRow: validated_row.fetch('source_row'),
+          url: validated_row.fetch('url'),
+          attributes: validated_row.fetch('attributes'),
+          provenance: validated_row.fetch('provenance'),
+          tagSources: validated_row.fetch('tag_sources'),
+          metadataUrl: validated_row.fetch('metadata_url')
+        }]
+      }
+
+      expect(response).to have_http_status(:ok)
+      expect(Post.order(:id).last.video_ms).to eq(2_500)
+    end
+
+    it 'returns a formal skipped result for an existing post' do
+      existing = create(:post, url: 'https://example.com/existing')
+      sign_in_as(member)
+
+      post '/posts/import', params: {
+        rows: [{
+          sourceRow: 1,
+          url: existing.url,
+          attributes: { title: 'ignored' },
+          provenance: { url: 'manual', title: 'manual' },
+          tagSources: { automatic: '', manual: '' }
+        }]
+      }
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include('created' => 0, 'skipped' => 1, 'failed' => 0)
+      expect(json.fetch('rows').first).to include(
+        'status' => 'skipped',
+        'existing_post_id' => existing.id
+      )
+    end
+  end
+end

backend/spec/requests/posts_spec.rb

@@ -9,11 +9,11 @@ RSpec.describe 'Posts API', type: :request do
   # resized_thumbnail! が MiniMagick 依存でコケやすいので request spec ではスタブしとくのが無難。
   before do
     allow_any_instance_of(Post).to receive(:resized_thumbnail!).and_return(true)
-    allow(Post).to receive(:resized_thumbnail_attachment) do
-      { io: StringIO.new('dummy'),
-        filename: 'resized_thumbnail.jpg',
-        content_type: 'image/jpeg' }
-    end
+    allow(Post).to receive(:resized_thumbnail_attachment).and_return(
+      io: StringIO.new('dummy'),
+      filename: 'resized_thumbnail.jpg',
+      content_type: 'image/jpeg'
+    )
   end
 
   def create_nico_tag!(name)
@@ -21,7 +21,8 @@ RSpec.describe 'Posts API', type: :request do
   end
 
   def dummy_upload
-    real_thumbnail_upload
+    # 中身は何でもいい（加工処理はスタブしてる）
+    Rack::Test::UploadedFile.new(StringIO.new('dummy'), 'image/jpeg', original_filename: 'dummy.jpg')
   end
 
   def real_thumbnail_upload
@@ -101,34 +102,34 @@ RSpec.describe 'Posts API', type: :request do
     end
   end
 
-  describe 'GET /posts' do
+  describe "GET /posts" do
     let!(:user) { create_member_user! }
 
-    let!(:tag_name) { TagName.create!(name: 'spec_tag') }
+    let!(:tag_name) { TagName.create!(name: "spec_tag") }
     let!(:tag) { Tag.create!(tag_name:, category: :general) }
     let!(:tag_name2) { TagName.create!(name: 'unko') }
     let!(:tag2) { Tag.create!(tag_name: tag_name2, category: :deerjikist) }
     let!(:alias_tag_name) { TagName.create!(name: 'manko', canonical: tag_name) }
 
     let!(:hit_post) do
-      Post.create!(uploaded_user: user, title: 'hello spec world',
+      Post.create!(uploaded_user: user, title: "hello spec world",
                    url: 'https://example.com/spec2').tap do |p|
         PostTag.create!(post: p, tag:)
       end
     end
 
     let!(:miss_post) do
-      Post.create!(uploaded_user: user, title: 'unrelated title',
+      Post.create!(uploaded_user: user, title: "unrelated title",
                    url: 'https://example.com/spec3').tap do |p|
         PostTag.create!(post: p, tag: tag2)
       end
     end
 
-    it 'returns posts with tag name in JSON' do
-      get '/posts'
+    it "returns posts with tag name in JSON" do
+      get "/posts"
 
       expect(response).to have_http_status(:ok)
-      posts = json.fetch('posts')
+      posts = json.fetch("posts")
 
       # 全postの全tagが name を含むこと
       expect(posts).not_to be_empty
@@ -141,8 +142,8 @@ RSpec.describe 'Posts API', type: :request do
       expect(json['count']).to be_an(Integer)
 
       # spec_tag を含む投稿が存在すること
-      all_tag_names = posts.flat_map { |p| p['tags'].map { |t| t['name'] } }
-      expect(all_tag_names).to include('spec_tag')
+      all_tag_names = posts.flat_map { |p| p["tags"].map { |t| t["name"] } }
+      expect(all_tag_names).to include("spec_tag")
     end
 
     it 'keeps children and sections keys in non-detail tag responses' do
@@ -161,9 +162,9 @@ RSpec.describe 'Posts API', type: :request do
       ])
     end
 
-    context 'when q is provided' do
-      it 'filters posts by q (hit case)' do
-        get '/posts', params: { tags: 'spec_tag' }
+    context "when q is provided" do
+      it "filters posts by q (hit case)" do
+        get "/posts", params: { tags: "spec_tag" }
 
         expect(response).to have_http_status(:ok)
         posts = json.fetch('posts')
@@ -181,8 +182,8 @@ RSpec.describe 'Posts API', type: :request do
         end
       end
 
-      it 'filters posts by q (hit case by alias)' do
-        get '/posts', params: { tags: 'manko' }
+      it "filters posts by q (hit case by alias)" do
+        get "/posts", params: { tags: "manko" }
 
         expect(response).to have_http_status(:ok)
         posts = json.fetch('posts')
@@ -200,11 +201,11 @@ RSpec.describe 'Posts API', type: :request do
         end
       end
 
-      it 'returns empty posts when nothing matches' do
-        get '/posts', params: { tags: 'no_such_keyword_12345' }
+      it "returns empty posts when nothing matches" do
+        get "/posts", params: { tags: "no_such_keyword_12345" }
 
         expect(response).to have_http_status(:ok)
-        expect(json.fetch('posts')).to eq([])
+        expect(json.fetch("posts")).to eq([])
         expect(json.fetch('count')).to eq(0)
       end
     end
@@ -692,73 +693,6 @@ RSpec.describe 'Posts API', type: :request do
     end
   end
 
-  describe 'GET /posts/metadata' do
-    let(:member) { create(:user, :member) }
-
-    it 'returns compact existing post data without fetching external metadata' do
-      sign_in_as(member)
-      existing = create(
-          :post,
-          title: 'existing post',
-          url: 'https://example.com/existing')
-      existing.thumbnail.attach(
-          io: StringIO.new('thumbnail'),
-          filename: 'thumbnail.jpg',
-          content_type: 'image/jpeg')
-      expect(PostMetadataFetcher).not_to receive(:fetch)
-
-      get '/posts/metadata', params: { url: 'https://example.com/existing' }
-
-      expect(response).to have_http_status(:ok)
-      expect(json).to include(
-          'url' => existing.url,
-          'existing_post_id' => existing.id,
-          'field_warnings' => { })
-      expect(json.fetch('existing_post')).to include(
-          'id' => existing.id,
-          'title' => existing.title,
-          'url' => existing.url,
-          'thumbnail_base' => existing.thumbnail_base)
-      expect(json.dig('existing_post', 'thumbnail'))
-          .to include('/rails/active_storage/blobs/proxy/')
-    end
-
-    it 'returns fetched metadata and structured display tags' do
-      sign_in_as(member)
-      allow(Preview::UrlSafety).to receive(:validate)
-      allow(PostMetadataFetcher).to receive(:fetch).and_return(
-          title: 'fetched title',
-          thumbnail_base: 'https://example.com/thumbnail.jpg',
-          tags: 'character:虹夏',
-          display_tags: [{ name: '虹夏', category: 'character' }],
-          original_created_from: nil,
-          original_created_before: nil,
-          duration: '1:00',
-          video_ms: 60_000)
-
-      get '/posts/metadata', params: { url: 'https://example.com/new' }
-
-      expect(response).to have_http_status(:ok)
-      expect(json).to include(
-          'url' => 'https://example.com/new',
-          'title' => 'fetched title',
-          'duration' => '1:00',
-          'video_ms' => 60_000,
-          'field_warnings' => { })
-      expect(json.fetch('display_tags')).to eq(
-          [{ 'name' => '虹夏', 'category' => 'character' }])
-    end
-
-    it 'returns URL validation errors as 422' do
-      sign_in_as(member)
-
-      get '/posts/metadata', params: { url: 'file:///etc/passwd' }
-
-      expect(response).to have_http_status(:unprocessable_entity)
-      expect(json.fetch('errors')).to have_key('url')
-    end
-  end
-
   describe 'POST /posts' do
     let(:member) { create(:user, :member) }
     let!(:alias_tag_name) { TagName.create!(name: 'manko', canonical: tag_name) }
@@ -778,46 +712,6 @@ RSpec.describe 'Posts API', type: :request do
       expect(response).to have_http_status(:forbidden)
     end
 
-    it 'dry-runs without persisting posts or new tags' do
-      sign_in_as(member)
-      counts = [Post.count, Tag.count, TagName.count]
-
-      post '/posts?dry=1', params: post_write_params(
-          title: 'dry-run post',
-          url: 'https://example.com/dry-run',
-          tags: 'character:new_dry_run_tag')
-
-      expect(response).to have_http_status(:ok)
-      expect(json).to include(
-          'url' => 'https://example.com/dry-run',
-          'tags' => 'new_dry_run_tag',
-          'existing_post_id' => nil)
-      expect(json.fetch('display_tags')).to eq(
-          [{ 'name' => 'new_dry_run_tag',
-             'category' => 'character',
-             'section_literals' => [] }])
-      expect([Post.count, Tag.count, TagName.count]).to eq(counts)
-    end
-
-    it 'dry-runs an existing URL without validating its upload' do
-      sign_in_as(member)
-      existing = create(:post, url: 'https://example.com/dry-existing')
-      invalid_upload = Rack::Test::UploadedFile.new(
-          StringIO.new('<svg></svg>'),
-          'image/png',
-          original_filename: 'thumbnail.png')
-
-      post '/posts?dry=1', params: post_write_params(
-          title: '',
-          url: existing.url,
-          tags: '',
-          thumbnail: invalid_upload)
-
-      expect(response).to have_http_status(:ok)
-      expect(json).to include('existing_post_id' => existing.id)
-      expect(json.fetch('field_warnings')).not_to have_key('thumbnail_base')
-    end
-
     it '201 and creates post + tags when member' do
       sign_in_as(member)
 
@@ -875,8 +769,7 @@ RSpec.describe 'Posts API', type: :request do
       )
 
       expect(response).to have_http_status(:created)
-      expect(open_transactions).to eq(
-          [baseline_open_transactions, baseline_open_transactions])
+      expect(open_transactions).to eq([baseline_open_transactions])
     end
 
     it 'returns 422 and does not create a post when thumbnail resize fails' do
@@ -934,7 +827,7 @@ RSpec.describe 'Posts API', type: :request do
 
       expect(response).to have_http_status(:unprocessable_entity)
       expect(json.fetch('errors')).to include(
-        'tags' => ['廃止済みタグがあります: deprecated_direct_tag']
+        'tags' => ['廃止済みタグは付与できません．']
       )
     end
 
@@ -1161,7 +1054,7 @@ RSpec.describe 'Posts API', type: :request do
       )
     end
 
-    context 'when nico tag already exists in tags' do
+    context "when nico tag already exists in tags" do
       before do
         Tag.find_undiscard_or_create_by!(
             tag_name: TagName.find_undiscard_or_create_by!(name: 'nico:nico_tag'),
@@ -1358,47 +1251,6 @@ RSpec.describe 'Posts API', type: :request do
     end
   end
 
-  describe 'POST /posts/bulk' do
-    let(:member) { create(:user, :member) }
-
-    it 'parses the manifest and indexed thumbnail parts' do
-      sign_in_as(member)
-      manifest = [{ 'url' => 'https://example.com/bulk',
-                    'title' => 'bulk post',
-                    'tags' => 'spec_tag',
-                    'parent_post_ids' => '' }]
-      creator = instance_double(
-          PostBulkCreator,
-          run: { results: [{ status: 'created', post: { id: 123 } }] })
-      allow(PostBulkCreator).to receive(:new).and_return(creator)
-
-      post '/posts/bulk', params: {
-          posts: JSON.generate(manifest),
-          thumbnails: { '0' => real_thumbnail_upload } }
-
-      expect(response).to have_http_status(:ok)
-      expect(json.fetch('results')).to eq(
-          [{ 'status' => 'created', 'post' => { 'id' => 123 } }])
-      expect(PostBulkCreator).to have_received(:new) do |arguments|
-        expect(arguments[:actor]).to eq(member)
-        expect(arguments[:posts]).to eq(manifest)
-        expect(arguments[:thumbnails].keys).to eq([0])
-        expect(arguments[:host]).to eq('http://www.example.com')
-      end
-    end
-
-    it 'rejects malformed manifests as a request-level error' do
-      sign_in_as(member)
-
-      post '/posts/bulk', params: {
-          posts: '{',
-          thumbnails: { '0' => real_thumbnail_upload } }
-
-      expect(response).to have_http_status(:bad_request)
-      expect(json.fetch('message')).to eq('posts manifest の JSON が不正です．')
-    end
-  end
-
   describe 'PUT /posts/:id' do
     let(:member) { create(:user, :member) }
 
@@ -1455,7 +1307,7 @@ RSpec.describe 'Posts API', type: :request do
       )
     end
 
-    context 'when nico tag already exists in tags' do
+    context "when nico tag already exists in tags" do
       before do
         Tag.find_undiscard_or_create_by!(
             tag_name: TagName.find_undiscard_or_create_by!(name: 'nico:nico_tag'),
@@ -1712,7 +1564,7 @@ RSpec.describe 'Posts API', type: :request do
         expect(post_record.reload.title).to eq('updated by other user')
       end
 
-      it 'returns mergeable 409 for stale non-conflicting tag changes without merge' do
+      it 'returns 409 with mergeable true when stale tag changes do not conflict but merge is not requested' do
         sign_in_as(member)
 
         base_version = create_post_version_for!(post_record.reload)
@@ -2419,9 +2271,9 @@ RSpec.describe 'Posts API', type: :request do
 
       expect(response).to have_http_status(:created)
       expect(Time.iso8601(json.fetch('original_created_from')))
-          .to eq(Time.utc(2020, 1, 1, 0, 0))
+          .to eq(Time.iso8601('2020-01-01T00:00Z'))
       expect(Time.iso8601(json.fetch('original_created_before')))
-          .to eq(Time.utc(2020, 1, 1, 0, 1))
+          .to eq(Time.iso8601('2020-01-01T00:01Z'))
     end
 
     it 'rejects unparseable original created timestamps on PUT /posts/:id' do

backend/spec/requests/wiki_body_search_pending_spec.rb

@@ -0,0 +1,27 @@
+require 'rails_helper'
+
+RSpec.describe 'Wiki body search', type: :request do
+  let!(:user) { create_member_user! }
+
+  it 'searches wiki pages by body text' do
+    pending '#336 で対応予定'
+
+    Wiki::Commit.create_content!(
+        tag_name: TagName.create!(name: 'wiki_body_search_hit'),
+        body: 'unique body keyword for wiki search',
+        created_by_user: user,
+        message: 'init')
+
+    Wiki::Commit.create_content!(
+        tag_name: TagName.create!(name: 'wiki_body_search_miss'),
+        body: 'ordinary body',
+        created_by_user: user,
+        message: 'init')
+
+    get '/wiki/search', params: { body: 'unique body keyword' }
+
+    expect(response).to have_http_status(:ok)
+    expect(json.map { |page| page['title'] }).to include('wiki_body_search_hit')
+    expect(json.map { |page| page['title'] }).not_to include('wiki_body_search_miss')
+  end
+end

backend/spec/requests/wiki_restore_pending_spec.rb

@@ -0,0 +1,37 @@
+require 'rails_helper'
+
+RSpec.describe 'Wiki restore', type: :request do
+  let!(:user) { create_member_user! }
+
+  def auth_headers user
+    { 'X-Transfer-Code' => user.inheritance_code }
+  end
+
+  it 'restores wiki page to previous version' do
+    pending '#337 で対応予定'
+
+    page =
+        Wiki::Commit.create_content!(
+            tag_name: TagName.create!(name: 'wiki_restore_page'),
+            body: 'v1',
+            created_by_user: user,
+            message: 'init')
+
+    v1 = page.wiki_versions.order(:version_no).last
+
+    Wiki::Commit.content!(
+        page:,
+        body: 'v2',
+        created_user: user,
+        message: 'edit',
+        base_revision_id: page.current_revision.id)
+
+    post "/wiki/#{ page.id }/restore",
+         params: { version_no: v1.version_no },
+         headers: auth_headers(user)
+
+    expect(response).to have_http_status(:ok)
+    expect(page.reload.body).to eq('v1')
+    expect(page.wiki_versions.order(:version_no).last.event_type).to eq('restore')
+  end
+end

backend/spec/services/post_bulk_creator_spec.rb

@@ -1,59 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe PostBulkCreator do
-  it 'limits workers to two and keeps failures in their request slots' do
-    actor = instance_double(User, id: 123)
-    allow(User).to receive(:find).with(123) {
-      instance_double(User, id: 123)
-    }
-    mutex = Mutex.new
-    active = 0
-    maximum_active = 0
-
-    allow(PostCreatePreflight).to receive(:new) do |attributes:, **|
-      preflight = instance_double(PostCreatePreflight)
-      allow(preflight).to receive(:run) do
-        mutex.synchronize do
-          active += 1
-          maximum_active = [maximum_active, active].max
-        end
-        sleep 0.02
-        mutex.synchronize { active -= 1 }
-        attributes.symbolize_keys.merge(
-            existing_post_id: nil,
-            field_warnings: { },
-            base_warnings: [])
-      end
-      preflight
-    end
-    allow(PostCreator).to receive(:new) do |attributes:, **|
-      creator = instance_double(PostCreator)
-      if attributes[:title] == 'broken'
-        allow(creator).to receive(:create!).and_raise(StandardError, 'broken')
-      else
-        post = instance_double(Post, id: attributes[:title].delete_prefix('post ').to_i)
-        allow(creator).to receive(:create!).and_return(post)
-      end
-      creator
-    end
-    posts = [
-        { 'title' => 'post 1', 'url' => 'https://example.com/1' },
-        { 'title' => 'broken', 'url' => 'https://example.com/2' },
-        { 'title' => 'post 3', 'url' => 'https://example.com/3' },
-        { 'title' => 'post 4', 'url' => 'https://example.com/4' }]
-
-    results = described_class.new(
-        actor:,
-        posts:,
-        thumbnails: { }).run.fetch(:results)
-
-    expect(maximum_active).to eq(2)
-    expect(results.length).to eq(posts.length)
-    expect(results.map { _1[:status] }).to eq(
-        ['created', 'failed', 'created', 'created'])
-    expect(results[0].dig(:post, :id)).to eq(1)
-    expect(results[1]).to include(status: 'failed', recoverable: false)
-    expect(results[2].dig(:post, :id)).to eq(3)
-    expect(results[3].dig(:post, :id)).to eq(4)
-  end
-end

backend/spec/services/post_create_plan_spec.rb

@@ -1,82 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe PostCreatePlan do
-  def create_tag! name, category
-    Tag.create!(name:, category:)
-  end
-
-  before do
-    create_tag!('タグ希望', :meta)
-    create_tag!('ニジラー情報不詳', :meta)
-  end
-
-  it 'plans direct and existing default tags without persisting records' do
-    counts = [TagName.count, Tag.count]
-
-    plan = described_class.new(
-        attributes: {
-            url: 'https://example.com/post',
-            title: 'title',
-            tags: 'character:new_character',
-            parent_post_ids: '' }).build!
-
-    expect(plan[:tags]).to eq('new_character')
-    expect(plan[:direct_tag_specs]).to eq(
-        [{ name: 'new_character', category: :character }])
-    expect(plan[:default_tag_specs]).to include(
-        { name: 'タグ希望', category: :meta },
-        { name: 'ニジラー情報不詳', category: :meta })
-    expect([TagName.count, Tag.count]).to eq(counts)
-  end
-
-  it 'resolves aliases and keeps tag sections separate from canonical names' do
-    canonical = create_tag!('虹夏', :character)
-    TagName.create!(name: 'にじか', canonical: canonical.tag_name)
-    create_tag!('動画', :meta)
-
-    plan = described_class.new(
-        attributes: {
-            url: 'https://example.com/video',
-            title: 'video',
-            tags: '動画 にじか[0:10-0:20]',
-            duration: '1:00',
-            parent_post_ids: '' }).build!
-
-    expect(plan[:tags].split).to include('動画', '虹夏[0:10-0:20]')
-    expect(plan[:display_tags]).to include(
-        { name: '虹夏',
-          category: 'character',
-          section_literals: ['[0:10-0:20]'] })
-    expect(plan[:video_ms]).to eq(60_000)
-  end
-
-  it 'validates a new tag name without persisting it' do
-    long_name = 'a' * 256
-    counts = [TagName.count, Tag.count]
-
-    expect {
-      described_class.new(
-          attributes: {
-              url: 'https://example.com/post',
-              title: 'title',
-              tags: long_name,
-              parent_post_ids: '' }).build!
-    }.to raise_error(ActiveRecord::RecordInvalid) { |error|
-      expect(error.record.errors[:tags]).not_to be_empty
-    }
-    expect([TagName.count, Tag.count]).to eq(counts)
-  end
-
-  it 'ignores duration when the planned tags do not include video' do
-    plan = described_class.new(
-        attributes: {
-            url: 'https://example.com/post',
-            title: 'title',
-            tags: 'ordinary_tag',
-            duration: 'invalid',
-            parent_post_ids: '' }).build!
-
-    expect(plan[:duration]).to eq('invalid')
-    expect(plan[:video_ms]).to be_nil
-  end
-end

backend/spec/services/post_creator_spec.rb

@@ -20,12 +20,12 @@ RSpec.describe PostCreator do
     allow(PostVersionRecorder).to receive(:record!)
   end
 
-  it 'prefers thumbnail_base over an explicit upload' do
-    expect(Post).not_to receive(:resized_thumbnail_attachment)
-    allow(Post).to receive(:remote_thumbnail_attachment).and_return(
-        io: StringIO.new('remote'),
+  it 'prefers an explicit upload over thumbnail_base' do
+    allow(Post).to receive(:resized_thumbnail_attachment).and_return(
+        io: StringIO.new('upload'),
         filename: 'resized_thumbnail.jpg',
         content_type: 'image/jpeg')
+    expect_any_instance_of(Post).not_to receive(:attach_thumbnail_from_url!)
 
     post = described_class.new(
         actor:,
@@ -41,12 +41,13 @@ RSpec.describe PostCreator do
   end
 
   it 'uses the common remote thumbnail attach path when thumbnail_base is given' do
-    expect(Post).to receive(:remote_thumbnail_attachment)
-        .with('https://example.com/thumb.jpg')
-        .and_return(
-            io: StringIO.new('thumbnail'),
-            filename: 'thumbnail.jpg',
-            content_type: 'image/jpeg')
+    expect_any_instance_of(Post).to receive(:attach_thumbnail_from_url!)
+        .with('https://example.com/thumb.jpg') do |post, _url|
+      post.thumbnail.attach(
+          io: StringIO.new('thumbnail'),
+          filename: 'thumbnail.jpg',
+          content_type: 'image/jpeg')
+    end
 
     post = described_class.new(
         actor:,
@@ -60,8 +61,8 @@ RSpec.describe PostCreator do
     expect(post.thumbnail).to be_attached
   end
 
-  it 'does not create a post when remote thumbnail fetch fails' do
-    allow(Post).to receive(:remote_thumbnail_attachment)
+  it 'keeps creating the post and records a warning when remote thumbnail fetch fails' do
+    allow_any_instance_of(Post).to receive(:attach_thumbnail_from_url!)
         .and_raise(Post::RemoteThumbnailFetchFailed, 'サムネール画像を取得できませんでした．')
     creator = described_class.new(
         actor:,
@@ -71,8 +72,11 @@ RSpec.describe PostCreator do
           thumbnail_base: 'https://example.com/thumb.jpg',
           tags: '' })
 
-    post_count = Post.count
-    expect { creator.create! }.to raise_error(Post::RemoteThumbnailFetchFailed)
-    expect(Post.count).to eq(post_count)
+    post = creator.create!
+
+    expect(post.thumbnail_base).to eq('https://example.com/thumb.jpg')
+    expect(post.thumbnail).not_to be_attached
+    expect(creator.field_warnings).to eq(
+        thumbnail_base: ['サムネール画像を取得できませんでした．'])
   end
 end

backend/spec/services/post_import_row_normaliser_spec.rb

@@ -0,0 +1,77 @@
+require 'rails_helper'
+
+RSpec.describe PostImportRowNormaliser do
+  def valid_row(overrides = { })
+    {
+      sourceRow: '1',
+      url: 'https://example.com/post',
+      metadataUrl: 'https://example.com/post',
+      attributes: { title: 'title', duration: '1' },
+      provenance: { url: 'manual', title: 'automatic' },
+      tagSources: { automatic: 'tag', manual: '' }
+    }.deep_merge(overrides)
+  end
+
+  describe '.normalise!' do
+    it 'normalises aliases and source rows into a permitted plain hash' do
+      row = ActionController::Parameters.new(valid_row)
+
+      expect(described_class.normalise!([row])).to eq([
+        {
+          'source_row' => 1,
+          'url' => 'https://example.com/post',
+          'metadata_url' => 'https://example.com/post',
+          'attributes' => { 'title' => 'title', 'duration' => '1' },
+          'provenance' => { 'url' => 'manual', 'title' => 'automatic' },
+          'tag_sources' => { 'automatic' => 'tag', 'manual' => '' }
+        }
+      ])
+    end
+
+    it 'normalises source rows before checking duplicates' do
+      rows = [valid_row, valid_row(sourceRow: 1, url: 'https://example.com/other')]
+
+      expect { described_class.normalise!(rows) }
+          .to raise_error(ArgumentError, '元行番号が重複しています．')
+    end
+
+    it 'rejects non-array batches and non-hash rows' do
+      expect { described_class.normalise!({}) }
+          .to raise_error(ArgumentError, '取込行の形式が不正です．')
+      expect { described_class.normalise!(['row']) }
+          .to raise_error(ArgumentError, '取込行の形式が不正です．')
+    end
+
+    it 'rejects unknown attributes and invalid field types' do
+      expect { described_class.normalise!([valid_row(attributes: { unknown: 'x' })]) }
+          .to raise_error(ArgumentError, '取込項目が不正です．')
+      expect { described_class.normalise!([valid_row(attributes: { title: [] })]) }
+          .to raise_error(ArgumentError, '取込項目の型が不正です．')
+      expect { described_class.normalise!([valid_row(attributes: { duration: false })]) }
+          .to raise_error(ArgumentError, '取込項目の型が不正です．')
+    end
+
+    it 'rejects unknown provenance and tag-source values' do
+      expect { described_class.normalise!([valid_row(provenance: { title: 'mapped' })]) }
+          .to raise_error(ArgumentError, '値の由来が不正です．')
+      expect { described_class.normalise!([valid_row(tagSources: { mapped: 'tag' })]) }
+          .to raise_error(ArgumentError, 'タグ由来の形式が不正です．')
+    end
+
+    it 'accepts warning fields only at the validation boundary' do
+      row = valid_row.merge(
+        fieldWarnings: { title: ['取得できませんでした．'] },
+        baseWarnings: ['確認してください．']
+      )
+
+      without_warnings = described_class.normalise!([row]).first
+      with_warnings = described_class.normalise!([row], allow_warning_fields: true).first
+
+      expect(without_warnings).not_to include('field_warnings', 'base_warnings')
+      expect(with_warnings).to include(
+        'field_warnings' => { 'title' => ['取得できませんでした．'] },
+        'base_warnings' => ['確認してください．']
+      )
+    end
+  end
+end

backend/spec/services/post_import_runner_spec.rb

@@ -0,0 +1,152 @@
+require 'rails_helper'
+
+RSpec.describe PostImportRunner do
+  let(:actor) { create(:user, :member) }
+
+  def row(source_row: 1, url: 'https://example.com/post')
+    {
+      sourceRow: source_row,
+      url:,
+      attributes: { title: 'title', tags: '' },
+      provenance: { url: 'manual', title: 'manual', tags: 'manual' },
+      tagSources: { automatic: '', manual: '' }
+    }
+  end
+
+  def preview(source_row: 1, errors: { }, skip_reason: nil, existing_post_id: nil)
+    {
+      source_row:,
+      attributes: { 'title' => 'title', 'tags' => '' },
+      validation_errors: errors,
+      skip_reason:,
+      existing_post_id:
+    }
+  end
+
+  it 'previews the whole batch once before processing individual rows' do
+    rows = [row, row(source_row: 2, url: 'https://example.com/two')]
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    expect(previewer).to receive(:preview_rows)
+        .with(
+          rows: satisfy { _1.map { |row_value| row_value['source_row'] } == [1, 2] },
+          fetch_metadata: false
+        )
+        .and_return([preview, preview(source_row: 2)])
+    allow(PostCreator).to receive(:new).and_return(
+      instance_double(PostCreator, create!: create(:post))
+    )
+
+    result = described_class.new(actor:, rows:).run
+
+    expect(result).to include(created: 2, skipped: 0, failed: 0)
+  end
+
+  it 'treats validation errors as failures before an existing skip' do
+    existing = create(:post)
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([
+      preview(errors: { url: ['URL が重複しています．'] },
+              skip_reason: 'existing', existing_post_id: existing.id)
+    ])
+    expect(PostCreator).not_to receive(:new)
+
+    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
+
+    expect(result).to include(
+      status: 'failed',
+      errors: { url: ['URL が重複しています．'] },
+      recoverable: true
+    )
+  end
+
+  it 'returns the existing post ID for skipped rows' do
+    existing = create(:post)
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([
+      preview(skip_reason: 'existing', existing_post_id: existing.id)
+    ])
+
+    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
+
+    expect(result).to eq(
+      source_row: 1,
+      status: 'skipped',
+      existing_post_id: existing.id
+    )
+  end
+
+  it 'converts a URL uniqueness validation race into a skip' do
+    existing = create(:post, url: 'https://example.com/race')
+    invalid = Post.new(url: existing.url)
+    invalid.errors.add(:url, :taken)
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([preview])
+    creator = instance_double(PostCreator)
+    allow(PostCreator).to receive(:new).and_return(creator)
+    allow(creator).to receive(:create!).and_raise(ActiveRecord::RecordInvalid.new(invalid))
+
+    result = described_class.new(
+      actor:,
+      rows: [row(url: 'https://EXAMPLE.com/race/')]
+    ).run.fetch(:rows).first
+
+    expect(result).to include(status: 'skipped', existing_post_id: existing.id)
+  end
+
+  it 're-raises RecordNotUnique errors unrelated to the posts URL index' do
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([preview])
+    creator = instance_double(PostCreator)
+    allow(PostCreator).to receive(:new).and_return(creator)
+    allow(creator).to receive(:create!)
+        .and_raise(ActiveRecord::RecordNotUnique, 'other_unique_index')
+
+    expect {
+      described_class.new(actor:, rows: [row]).run
+    }.to raise_error(ActiveRecord::RecordNotUnique)
+  end
+
+  it 'converts a posts URL index race into a skip' do
+    existing = create(:post, url: 'https://example.com/index-race')
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([preview])
+    creator = instance_double(PostCreator)
+    allow(PostCreator).to receive(:new).and_return(creator)
+    allow(creator).to receive(:create!).and_raise(
+      ActiveRecord::RecordNotUnique,
+      'duplicate key index_posts_on_url'
+    )
+
+    result = described_class.new(
+      actor:,
+      rows: [row(url: 'https://EXAMPLE.com/index-race/')]
+    ).run.fetch(:rows).first
+
+    expect(result).to include(status: 'skipped', existing_post_id: existing.id)
+  end
+
+  it 'returns thumbnail warnings from PostCreator on a created row' do
+    previewer = instance_double(PostImportPreviewer)
+    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
+    allow(previewer).to receive(:preview_rows).and_return([preview])
+    created_post = create(:post)
+    creator = instance_double(
+        PostCreator,
+        create!: created_post,
+        field_warnings: { thumbnail_base: ['サムネール画像を取得できませんでした．'] })
+    allow(PostCreator).to receive(:new).and_return(creator)
+
+    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
+
+    expect(result).to include(
+      status: 'created',
+      field_warnings: { thumbnail_base: ['サムネール画像を取得できませんでした．'] }
+    )
+  end
+end

backend/spec/services/post_import_url_list_parser_spec.rb

@@ -0,0 +1,40 @@
+require 'rails_helper'
+
+RSpec.describe PostImportUrlListParser do
+  describe '.parse' do
+    it 'trims URLs, ignores blank lines, and preserves source line numbers' do
+      source = "  https://example.com/one  \r\n\r\nhttps://example.com/two\n"
+
+      expect(described_class.parse(source)).to eq([
+        { source_row: 1, url: 'https://example.com/one' },
+        { source_row: 3, url: 'https://example.com/two' }
+      ])
+    end
+
+    it 'rejects an empty URL list' do
+      expect { described_class.parse(" \n\r\n") }
+          .to raise_error(ArgumentError, 'URL を入力してください．')
+    end
+
+    it 'rejects more than 100 non-empty rows' do
+      source = 101.times.map { |index| "https://example.com/#{ index }" }.join("\n")
+
+      expect { described_class.parse(source) }
+          .to raise_error(ArgumentError, '取込件数は 100 件までです．')
+    end
+
+    it 'includes the original line number in an oversized URL error' do
+      source = "\n#{ 'a' * (described_class::MAX_URL_BYTES + 1) }"
+
+      expect { described_class.parse(source) }
+          .to raise_error(ArgumentError, '2 行目: URL が長すぎます．')
+    end
+
+    it 'rejects an oversized request before parsing rows' do
+      source = 'a' * (described_class::MAX_BYTES + 1)
+
+      expect { described_class.parse(source) }
+          .to raise_error(ArgumentError, '入力が大きすぎます．')
+    end
+  end
+end

backend/spec/services/post_thumbnail_upload_validator_spec.rb

@@ -1,52 +0,0 @@
-require 'rails_helper'
-require 'base64'
-require 'tempfile'
-
-RSpec.describe PostThumbnailUploadValidator do
-  def with_upload bytes, content_type:, filename:
-    tempfile = Tempfile.new(['thumbnail-upload', File.extname(filename)])
-    tempfile.binmode
-    tempfile.write(bytes)
-    tempfile.rewind
-    upload = ActionDispatch::Http::UploadedFile.new(
-        tempfile:,
-        filename:,
-        type: content_type)
-    yield upload
-  ensure
-    tempfile&.close!
-  end
-
-  it 'accepts a raster upload after decoding and rewinds it' do
-    gif = Base64.decode64('R0lGODdhAQABAIABAP///wAAACwAAAAAAQABAAACAkQBADs=')
-
-    with_upload(gif, content_type: 'image/gif', filename: 'thumbnail.gif') do |upload|
-      expect { described_class.validate!(upload) }.not_to raise_error
-      expect(upload.read(6)).to eq('GIF87a')
-    end
-  end
-
-  it 'rejects SVG content disguised as a raster MIME type' do
-    with_upload(
-        '<svg width="10" height="10"></svg>',
-        content_type: 'image/png',
-        filename: 'thumbnail.png') do |upload|
-      expect { described_class.validate!(upload) }
-          .to raise_error(
-              described_class::InvalidUpload,
-              'サムネイル画像の形式が不正です．')
-    end
-  end
-
-  it 'rejects non-raster content disguised as an image' do
-    with_upload(
-        '%PDF-1.7',
-        content_type: 'image/png',
-        filename: 'thumbnail.png') do |upload|
-      expect { described_class.validate!(upload) }
-          .to raise_error(
-              described_class::InvalidUpload,
-              'サムネイル画像の形式が不正です．')
-    end
-  end
-end

backend/spec/services/preview/thumbnail_fetcher_spec.rb

@@ -2,7 +2,7 @@ require 'rails_helper'
 
 RSpec.describe Preview::ThumbnailFetcher do
   describe '.fetch' do
-    it 'accepts svg thumbnails for the common safe rasterisation path' do
+    it 'rejects svg thumbnails' do
       page = Preview::HttpFetcher::Response.new(
           '<meta property="og:image" content="https://example.com/thumb.svg">',
           'text/html',
@@ -12,9 +12,8 @@ RSpec.describe Preview::ThumbnailFetcher do
           'image/svg+xml',
           'https://example.com/thumb.svg')
 
-      allow(Preview::UrlSafety).to receive(:validate) do |url|
-        [URI.parse(url), ['203.0.113.10']]
-      end
+      allow(Preview::UrlSafety).to receive(:validate)
+          .and_return([URI.parse('https://example.com/page'), ['203.0.113.10']])
       allow(Preview::HttpFetcher).to receive(:fetch)
           .with('https://example.com/page', max_bytes: described_class::HTML_MAX_BYTES)
           .and_return(page)
@@ -22,7 +21,9 @@ RSpec.describe Preview::ThumbnailFetcher do
           .with('https://example.com/thumb.svg')
           .and_return(svg)
 
-      expect(described_class.fetch('https://example.com/page')).to eq('<svg></svg>')
+      expect {
+        described_class.fetch('https://example.com/page')
+      }.to raise_error(Preview::ThumbnailFetcher::GenerationFailed)
     end
 
     it 'accepts allowed image content type with parameters' do
@@ -31,13 +32,12 @@ RSpec.describe Preview::ThumbnailFetcher do
           'text/html',
           'https://example.com/page')
       image = Preview::HttpFetcher::Response.new(
-          "\xFF\xD8\xFFjpeg-bytes".b,
+          'jpeg-bytes',
           'image/jpeg; charset=binary',
           'https://example.com/thumb.jpg')
 
-      allow(Preview::UrlSafety).to receive(:validate) do |url|
-        [URI.parse(url), ['203.0.113.10']]
-      end
+      allow(Preview::UrlSafety).to receive(:validate)
+          .and_return([URI.parse('https://example.com/page'), ['203.0.113.10']])
       allow(Preview::HttpFetcher).to receive(:fetch)
           .with('https://example.com/page', max_bytes: described_class::HTML_MAX_BYTES)
           .and_return(page)
@@ -45,8 +45,7 @@ RSpec.describe Preview::ThumbnailFetcher do
           .with('https://example.com/thumb.jpg')
           .and_return(image)
 
-      expect(described_class.fetch('https://example.com/page'))
-          .to eq("\xFF\xD8\xFFjpeg-bytes".b)
+      expect(described_class.fetch('https://example.com/page')).to eq('jpeg-bytes')
     end
   end
 

backend/spec/tasks/nico_sync_spec.rb

@@ -1,10 +1,10 @@
-require 'rails_helper'
+require "rails_helper"
 
 
-RSpec.describe 'nico:sync' do
+RSpec.describe "nico:sync" do
   def stub_python(json_array)
     status = instance_double(Process::Status, success?: true)
-    allow(Open3).to receive(:capture3).and_return([json_array.to_json, '', status])
+    allow(Open3).to receive(:capture3).and_return([json_array.to_json, "", status])
   end
 
   def create_tag!(name, category:)
@@ -16,21 +16,21 @@ RSpec.describe 'nico:sync' do
     NicoTagRelation.create!(nico_tag_id: nico_tag.id, tag_id: tag.id)
   end
 
-  it '既存 post を見つけて、nico tag と linked tag を追加し、差分が出たら bot を付ける' do
+  it "既存 post を見つけて、nico tag と linked tag を追加し、差分が出たら bot を付ける" do
     # 既存 post（正規表現で拾われるURL）
     post = Post.create!(
-      title: 'old',
-      url: 'https://www.nicovideo.jp/watch/sm9',
+      title: "old",
+      url: "https://www.nicovideo.jp/watch/sm9",
       uploaded_user: nil
     )
 
     # 既存の非nicoタグ（kept_non_nico_ids）
-    kept_general = create_tag!('spec_kept', category: 'general')
+    kept_general = create_tag!("spec_kept", category: "general")
     PostTag.create!(post: post, tag: kept_general)
 
     # 追加される linked tag を準備（nico tag に紐付く一般タグ）
-    linked = create_tag!('spec_linked', category: 'general')
-    nico = create_tag!('nico:AAA', category: 'nico')
+    linked = create_tag!("spec_linked", category: "general")
+    nico = create_tag!("nico:AAA", category: "nico")
     link_nico_to_tag!(nico, linked)
 
     # bot / tagme は task 内で使うので作っておく（Tag.bot/tagme がある前提）
@@ -46,22 +46,22 @@ RSpec.describe 'nico:sync' do
         'deleted_at' => '2026-01-31 00:00:00' }])
 
     # 外部HTTPは今回「既存 post なので呼ばれない」はずだが、念のため塞ぐ
-    allow(URI).to receive(:open).and_return(StringIO.new('<html></html>'))
+    allow(URI).to receive(:open).and_return(StringIO.new("<html></html>"))
 
-    run_rake_task('nico:sync')
+    run_rake_task("nico:sync")
 
     post.reload
-    active_tag_names = post.tags.joins(:tag_name).pluck('tag_names.name')
+    active_tag_names = post.tags.joins(:tag_name).pluck("tag_names.name")
 
-    expect(active_tag_names).to include('spec_kept')
-    expect(active_tag_names).to include('nico:AAA')
-    expect(active_tag_names).to include('spec_linked')
+    expect(active_tag_names).to include("spec_kept")
+    expect(active_tag_names).to include("nico:AAA")
+    expect(active_tag_names).to include("spec_linked")
 
     expect(post.original_created_from).to eq(Time.iso8601('2026-01-01T03:34:00Z'))
     expect(post.original_created_before).to eq(Time.iso8601('2026-01-01T03:35:00Z'))
 
     # 差分が出るので bot が付く（kept_non_nico_ids != desired_non_nico_ids）
-    expect(active_tag_names).to include('bot操作')
+    expect(active_tag_names).to include("bot操作")
   end
 
   it '既存 post のサムネール取得に共通 attach 経路を使ふ' do
@@ -73,11 +73,11 @@ RSpec.describe 'nico:sync' do
     Tag.tagme
 
     stub_python([{ 'code' => 'sm9', 'title' => 't', 'tags' => [] }])
-    allow(URI).to receive(:open) do
-      StringIO.new(
-          '<meta name="thumbnail" content="https://example.com/thumb.jpg">')
-    end
-    expect_any_instance_of(Post).to receive(:attach_thumbnail_from_url!)
+    allow(URI).to receive(:open)
+        .and_return(
+            StringIO.new(
+                '<meta name="thumbnail" content="https://example.com/thumb.jpg">'))
+    expect(post).to receive(:attach_thumbnail_from_url!)
         .with('https://example.com/thumb.jpg')
 
     run_rake_task('nico:sync')
@@ -92,45 +92,43 @@ RSpec.describe 'nico:sync' do
     Tag.tagme
 
     stub_python([{ 'code' => 'sm9', 'title' => 't', 'tags' => [] }])
-    allow(URI).to receive(:open) do
-      StringIO.new(
-          '<meta name="thumbnail" content="https://example.com/thumb.jpg">')
-    end
-    calls = 0
-    allow_any_instance_of(Post).to receive(:attach_thumbnail_from_url!) do
-      calls += 1
-      raise Post::RemoteThumbnailFetchFailed, 'failed'
-    end
+    allow(URI).to receive(:open)
+        .and_return(
+            StringIO.new(
+                '<meta name="thumbnail" content="https://example.com/thumb.jpg">'))
+    expect(post).to receive(:attach_thumbnail_from_url!)
+        .with('https://example.com/thumb.jpg')
+        .twice
+        .and_raise(Post::RemoteThumbnailFetchFailed, 'failed')
 
     2.times do
       run_rake_task('nico:sync')
     end
-    expect(calls).to eq(2)
   end
 
-  it '既存 post にあった古い nico tag は active から外され、履歴として discard される' do
+  it "既存 post にあった古い nico tag は active から外され、履歴として discard される" do
     post = Post.create!(
-      title: 'old',
-      url: 'https://www.nicovideo.jp/watch/sm9',
+      title: "old",
+      url: "https://www.nicovideo.jp/watch/sm9",
       uploaded_user: nil
     )
 
     # 旧nicoタグ（今回の同期結果に含まれない）
-    old_nico = create_tag!('nico:OLD', category: 'nico')
+    old_nico = create_tag!("nico:OLD", category: "nico")
     old_pt = PostTag.create!(post: post, tag: old_nico)
     expect(old_pt.discarded_at).to be_nil
 
     # 今回は NEW のみ欲しい
-    new_nico = create_tag!('nico:NEW', category: 'nico')
+    new_nico = create_tag!("nico:NEW", category: "nico")
 
     # bot/tagme 念のため
     Tag.bot
     Tag.tagme
 
-    stub_python([{ 'code' => 'sm9', 'title' => 't', 'tags' => ['NEW'] }])
-    allow(URI).to receive(:open).and_return(StringIO.new('<html></html>'))
+    stub_python([{ "code" => "sm9", "title" => "t", "tags" => ["NEW"] }])
+    allow(URI).to receive(:open).and_return(StringIO.new("<html></html>"))
 
-    run_rake_task('nico:sync')
+    run_rake_task("nico:sync")
 
     # OLD は active から外れる（discarded_at が入る）
     old_pts = PostTag.where(post_id: post.id, tag_id: old_nico.id).order(:id).to_a
@@ -138,9 +136,9 @@ RSpec.describe 'nico:sync' do
 
     # NEW は active にいる
     post.reload
-    active_names = post.tags.joins(:tag_name).pluck('tag_names.name')
-    expect(active_names).to include('nico:NEW')
-    expect(active_names).not_to include('nico:OLD')
+    active_names = post.tags.joins(:tag_name).pluck("tag_names.name")
+    expect(active_names).to include("nico:NEW")
+    expect(active_names).not_to include("nico:OLD")
   end
 
   def snapshot_tags(post)

frontend/src/App.tsx

@@ -1,9 +1,8 @@
 import { AnimatePresence, LayoutGroup, MotionConfig, motion } from 'framer-motion'
 import { Fragment, useEffect, useMemo, useState } from 'react'
-import { createBrowserRouter,
+import { BrowserRouter,
 	 Navigate,
 	 Route,
-	 RouterProvider,
 	 Routes,
 	 useLocation } from 'react-router-dom'
 
@@ -155,7 +154,7 @@ const PostDetailRoute = ({ user }: { user: User | null }) => {
 }
 
 
-const RoutedApp: FC = () => {
+const App: FC = () => {
   const [user, setUser] = useState<User | null> (null)
   const [status, setStatus] = useState (200)
   const behaviourSettings = useClientBehaviourSettings ()
@@ -254,46 +253,42 @@ const RoutedApp: FC = () => {
   }
 
   return (
-      <DialogueProvider>
-	<UnsavedChangesGuardProvider>
-	  <KeyboardShortcutsProvider>
-	  <MotionConfig
-	      reducedMotion={
-		  animationMode === 'normal'
-		  ? 'never'
-		  : animationMode === 'reduced'
-		    ? 'user'
-		    : 'always'
-	      }>
-	    <LayoutWrapper>
-	      <motion.div
-		  layout={animationMode === 'off' ? false : 'position'}
-		  transition={{ layout: appLayoutTransition }}
-		  className="relative flex h-dvh w-full flex-col overflow-y-hidden">
-		<TopNav user={user}/>
-		<RouteTransitionWrapper
-		    animationMode={animationMode}
-		    user={user}
-		    setUser={setUser}/>
-	      </motion.div>
-	    </LayoutWrapper>
-	  </MotionConfig>
+      <>
+	<RouteBlockerOverlay/>
+	{import.meta.env.DEV && <DevModeWatermark/>}
 
-	  <Toaster/>
-	  </KeyboardShortcutsProvider>
-	</UnsavedChangesGuardProvider>
-      </DialogueProvider>)
+	<BrowserRouter>
+	  <DialogueProvider>
+	    <UnsavedChangesGuardProvider>
+	      <KeyboardShortcutsProvider>
+	      <MotionConfig
+		  reducedMotion={
+		      animationMode === 'normal'
+		      ? 'never'
+		      : animationMode === 'reduced'
+			? 'user'
+			: 'always'
+		  }>
+		<LayoutWrapper>
+		  <motion.div
+		      layout={animationMode === 'off' ? false : 'position'}
+		      transition={{ layout: appLayoutTransition }}
+		      className="relative flex flex-col h-dvh w-full overflow-y-hidden">
+		    <TopNav user={user}/>
+		    <RouteTransitionWrapper
+			animationMode={animationMode}
+			user={user}
+			setUser={setUser}/>
+		  </motion.div>
+		</LayoutWrapper>
+	      </MotionConfig>
+
+	      <Toaster/>
+	      </KeyboardShortcutsProvider>
+	    </UnsavedChangesGuardProvider>
+	  </DialogueProvider>
+	</BrowserRouter>
+      </>)
 }
 
-const router = createBrowserRouter ([{
-    path: '*',
-    element: <RoutedApp/> }])
-
-const App: FC = () => (
-    <>
-      <RouteBlockerOverlay/>
-      {import.meta.env.DEV && <DevModeWatermark/>}
-      <RouterProvider router={router}/>
-    </>)
-
 export default App

frontend/src/components/PostEditForm.test.tsx

@@ -78,23 +78,19 @@ describe ('PostEditForm', () => {
 
     render (<PostEditForm post={post} onSave={vi.fn ()}/>)
 
-    expect (screen.getByText ('動画時間').parentElement?.querySelector ('input'))
-	.toHaveValue ('180.5')
+    expect (screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23')).toHaveValue ('180.5')
 
     const tags = screen.getAllByRole ('textbox')[2]
     fireEvent.change (tags, { target: { value: 'general-tag' } })
-    expect (screen.queryByText ('動画時間')).not.toBeInTheDocument ()
+    expect (screen.queryByPlaceholderText ('例: 2 / 2.5 / 1:23')).not.toBeInTheDocument ()
 
     fireEvent.change (tags, {
       target: { value: '動画 general-tag' },
     })
-    expect (screen.getByText ('動画時間').parentElement?.querySelector ('input'))
-	.toHaveValue ('180.5')
+    expect (screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23')).toHaveValue ('180.5')
   })
 
-  it (
-      'shows deduplicated original-created endpoint errors on the shared datetime field',
-      async () => {
+  it ('shows deduplicated original-created endpoint errors on the shared datetime field', async () => {
     const post = buildPost ()
     api.isApiError.mockReturnValue (true)
     postsApi.updatePost.mockRejectedValueOnce ({
@@ -116,5 +112,5 @@ describe ('PostEditForm', () => {
     expect (await screen.findByText ('日時を確認してください．')).toBeInTheDocument ()
     expect (screen.getByText ('終了を確認してください．')).toBeInTheDocument ()
     expect (screen.getAllByText ('日時を確認してください．')).toHaveLength (1)
-      })
+  })
 })

frontend/src/components/PostOriginalCreatedTimeField.test.tsx

@@ -73,7 +73,7 @@ describe ('PostOriginalCreatedTimeField', () => {
             setOriginalCreatedBefore={vi.fn ()}/>,
     )
 
-    const input = screen.getByDisplayValue ('2024-01-01T12:34')
+    const input = screen.getDisplayValue ('2024-01-01T12:34')
     fireEvent.change (input, { target: { value: '2024-01-01T12:35' } })
 
     expect (setFrom).toHaveBeenCalledWith ('2024-01-01T03:35Z')

frontend/src/components/PrefetchLink.tsx

@@ -6,6 +6,7 @@ import { createPath, useNavigate } from 'react-router-dom'
 import { useOverlayStore } from '@/components/RouteBlockerOverlay'
 import { prefetchForURL } from '@/lib/prefetchers'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
+import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
 import { cn } from '@/lib/utils'
 
 import type { AnchorHTMLAttributes, MouseEvent, TouchEvent } from 'react'
@@ -35,6 +36,7 @@ export default forwardRef<HTMLAnchorElement, Props> (({
   const navigate = useNavigate ()
   const qc = useQueryClient ()
   const behaviourSettings = useClientBehaviourSettings ()
+  const { confirmDiscardNavigation } = useUnsavedChangesGuard ()
   const linkPreloadMode = behaviourSettings.linkPreload ?? 'intent'
   const path = useMemo (
       () => typeof to === 'string' ? to : createPath (to),
@@ -43,6 +45,10 @@ export default forwardRef<HTMLAnchorElement, Props> (({
   const url = useMemo (() => {
     return (new URL (path, window.location.origin)).toString ()
   }, [path])
+  const nextPathname = useMemo (
+      () => (new URL (path, window.location.origin)).pathname,
+      [path],
+  )
   const setOverlay = useOverlayStore (s => s.setActive)
 
   const doPrefetch = async () => {
@@ -87,6 +93,13 @@ export default forwardRef<HTMLAnchorElement, Props> (({
 
       ev.preventDefault ()
 
+      if (nextPathname !== window.location.pathname)
+	{
+	  const confirmed = await confirmDiscardNavigation ()
+	  if (!(confirmed))
+	    return
+	}
+
       flushSync (() => {
 	setOverlay (true)
       })

frontend/src/components/TagLink.tsx

@@ -4,13 +4,9 @@ import { cn } from '@/lib/utils'
 
 import type { ComponentProps, CSSProperties, FC, HTMLAttributes } from 'react'
 
-import type { Category, Tag } from '@/types'
+import type { Tag } from '@/types'
 
-type LightweightTag = {
-    name:     string
-    category: Category }
-
-type FullCommonProps = {
+type CommonProps = { 
     tag:        Tag
     nestLevel?: number
     truncateOnMobile?: boolean
@@ -18,43 +14,18 @@ type FullCommonProps = {
     withCount?: boolean }
 
 type PropsWithLink =
-    & FullCommonProps
+    & CommonProps
     & { linkFlg?: true }
     & Partial<ComponentProps<typeof PrefetchLink>>
 
 type PropsWithoutLink =
-    & FullCommonProps
+    & CommonProps
     & { linkFlg: false }
     & Partial<HTMLAttributes<HTMLSpanElement>>
 
-type LightweightPropsWithLink =
-    & {
-	tag:              LightweightTag
-	nestLevel?:       number
-	truncateOnMobile?: boolean
-	withWiki:         false
-	withCount:        false
-	linkFlg?:         true }
-    & Partial<ComponentProps<typeof PrefetchLink>>
-
-type LightweightPropsWithoutLink =
-    & {
-	tag:              LightweightTag
-	nestLevel?:       number
-	truncateOnMobile?: boolean
-	withWiki:         false
-	withCount:        false
-	linkFlg:          false }
-    & Partial<HTMLAttributes<HTMLSpanElement>>
-
 type Props =
     | PropsWithLink
     | PropsWithoutLink
-    | LightweightPropsWithLink
-    | LightweightPropsWithoutLink
-
-const isFullTag = (tag: Tag | LightweightTag): tag is Tag =>
-    'id' in tag
 
 
 const TagLink: FC<Props> = ({ tag,
@@ -75,18 +46,16 @@ const TagLink: FC<Props> = ({ tag,
   const spanClass = 'tag-link-colour'
   const linkClass = 'tag-link-colour tag-link-hover-colour'
   const textClass = 'group min-w-0 max-w-full overflow-hidden align-bottom'
+  const rootClass =
+      'inline-flex min-w-0 max-w-full flex-nowrap items-stretch align-baseline gap-x-1 md:items-baseline'
   const markerWrapClass = 'shrink-0 self-start md:self-auto'
   const countClass = 'shrink-0 self-end md:self-auto'
-  const matchedAlias = isFullTag (tag) ? tag.matchedAlias : null
   const textTitle = title
-      ?? (matchedAlias == null ? tag.name : `${ matchedAlias } → ${ tag.name }`)
+      ?? (tag.matchedAlias == null ? tag.name : `${ tag.matchedAlias } → ${ tag.name }`)
 
   return (
-      <span
-	  className={cn (
-	      'inline-flex min-w-0 max-w-full flex-nowrap items-stretch align-baseline',
-	      'gap-x-1 md:items-baseline')}>
-	{(linkFlg && withWiki && isFullTag (tag)) && (
+      <span className={rootClass}>
+	{(linkFlg && withWiki) && (
 	    <span className={markerWrapClass}>
 	      {(tag.materialId != null || tag.hasWiki || tag.hasDeerjikists)
 	       ? (
@@ -149,7 +118,7 @@ const TagLink: FC<Props> = ({ tag,
 		style={{ paddingLeft: `${ (nestLevel - 1) }rem` }}>
 	      ↳
 	    </span>)}
-	{matchedAlias != null && (
+	{tag.matchedAlias != null && (
 	    <>
 	      <span
 		  title={textTitle}
@@ -157,7 +126,7 @@ const TagLink: FC<Props> = ({ tag,
 		  style={colourStyle}
 		  {...props}>
 		<ResponsiveMarqueeText
-		    text={matchedAlias}
+		    text={tag.matchedAlias}
 		    title={textTitle}
 		    truncateOnMobile={truncateOnMobile}/>
 	      </span>
@@ -187,7 +156,7 @@ const TagLink: FC<Props> = ({ tag,
 		  title={textTitle}
 		  truncateOnMobile={truncateOnMobile}/>
 	    </span>)}
-	{(withCount && isFullTag (tag)) && (
+	{withCount && (
 	    <span className={countClass}>{tag.postCount}</span>)}
       </span>)
 }

frontend/src/components/TopNav.test.tsx

@@ -17,19 +17,21 @@ describe ('menuOutline', () => {
     for (const role of ['member', 'admin'] as const)
       {
 	expect (submenuItem (role, '広場', '追加')?.visible).toBe (true)
+	expect (submenuItem (role, '広場', '取込')?.visible).toBe (true)
 	expect (submenuItem (role, '素材', '追加')?.visible).toBe (true)
 	expect (submenuItem (role, 'Wiki', '新規')?.visible).toBe (true)
 	expect (submenuItem (role, 'Wiki', '編輯')?.visible).toBe (true)
       }
 
     expect (submenuItem ('guest', '広場', '追加')?.visible).toBe (false)
+    expect (submenuItem ('guest', '広場', '取込')?.visible).toBe (false)
     expect (submenuItem ('guest', '素材', '追加')?.visible).toBe (false)
     expect (submenuItem ('guest', 'Wiki', '新規')?.visible).toBe (false)
     expect (submenuItem ('guest', 'Wiki', '編輯')?.visible).toBe (false)
   })
 
-  it ('uses /posts/new as the post creation entrypoint', () => {
-    expect (submenuItem ('member', '広場', '追加')?.to).toBe ('/posts/new')
+  it ('uses /posts/new as the import entrypoint', () => {
+    expect (submenuItem ('member', '広場', '取込')?.to).toBe ('/posts/new')
   })
 
   it ('keeps material suppression admin-only', () => {

frontend/src/components/dialogues/DialogueProvider.test.tsx

@@ -80,9 +80,7 @@ describe ('DialogueProvider', () => {
     expect (dialogue).toHaveClass ('max-h-[calc(100dvh-1rem)]', 'flex-col', 'max-w-3xl')
     await waitFor (() => expect (screen.getByRole ('button', { name: '左操作' }))
 	.toBeInTheDocument ())
-    expect (screen.getByRole ('button', { name: '左操作' })).toHaveClass (
-	'w-full',
-	'md:w-auto')
+    expect (screen.getByRole ('button', { name: '左操作' })).toHaveClass ('w-full', 'sm:w-auto')
     fireEvent.click (screen.getByRole ('button', { name: '左操作' }))
 
     await waitFor (() => expect (action).toHaveBeenCalledTimes (1))

frontend/src/components/posts/PostCreationDataFieldsUsage.test.tsx

@@ -2,6 +2,8 @@ import { render, screen } from '@testing-library/react'
 import { describe, expect, it, vi } from 'vitest'
 
 import { buildPostImportRow } from '@/test/postImportFactories'
+import { buildUser } from '@/test/factories'
+import { renderWithProviders } from '@/test/render'
 
 import type { DialogueFormControls } from '@/lib/dialogues/useDialogue'
 
@@ -12,6 +14,14 @@ vi.mock ('@/components/posts/PostCreationDataFields', () => ({
 }))
 
 describe ('PostCreationDataFields usage', () => {
+  it ('is used by PostNewPage', async () => {
+    const { default: PostNewPage } = await import ('@/pages/posts/PostNewPage')
+
+    renderWithProviders (<PostNewPage user={buildUser ({ role: 'member' })}/>)
+
+    expect (screen.getByTestId ('shared-fields')).toBeInTheDocument ()
+  })
+
   it ('is used by PostImportRowForm', async () => {
     const { default: PostImportRowForm } = await import (
         '@/components/posts/import/PostImportRowForm')

frontend/src/components/posts/import/PostImportRowForm.test.tsx

@@ -135,7 +135,7 @@ describe ('PostImportRowForm', () => {
   })
 
   it (
-      'shows upload input only when the thumbnail URL is blank',
+      'shows the shared creation field order without duration and without file upload UI',
       async () => {
     let actions: DialogueFormAction[] = []
     const controls: DialogueFormControls = {
@@ -164,9 +164,7 @@ describe ('PostImportRowForm', () => {
       'オリジナルの作成日時',
       'タグ',
       '親投稿'])
-    expect (container.querySelector ('input[type="file"]')).toHaveAttribute (
-	'accept',
-	'image/*')
+    expect (container.querySelector ('input[type="file"]')).toBeNull ()
     expect (screen.queryByPlaceholderText ('例: 2 / 2.5 / 1:23')).not.toBeInTheDocument ()
     expect (screen.getByDisplayValue ('tag1')).toBeInTheDocument ()
 

frontend/src/components/posts/import/PostImportRowForm.tsx

@@ -10,8 +10,8 @@ import { hasThumbnailBaseValue, hasVideoTag } from '@/lib/postImportRows'
 
 import type { FC } from 'react'
 
+import type { PostImportEditableDraft, PostImportRow } from '@/lib/postImportSession'
 import type { DialogueFormControls } from '@/lib/dialogues/useDialogue'
-import type { PostImportEditableDraft, PostImportRow } from '@/lib/postImportTypes'
 
 type Draft = PostImportEditableDraft
 

frontend/src/components/posts/import/PostImportRowSummary.tsx

@@ -1,25 +1,21 @@
 import FieldError from '@/components/common/FieldError'
-import PostImportTagLinks from '@/components/posts/import/PostImportTagLinks'
 import { Button } from '@/components/ui/button'
 import PostImportThumbnailPreview from '@/components/posts/import/PostImportThumbnailPreview'
 import PostImportStatusBadge from '@/components/posts/import/PostImportStatusBadge'
 import { displayPostImportStatus } from '@/components/posts/import/postImportRowStatus'
-import {
-    canEditReviewRow,
-    canRetryResultRow,
-    hasVideoTag,
-} from '@/lib/postImportRows'
+import { hasVideoTag } from '@/lib/postImportSession'
+import { canEditReviewRow, canRetryResultRow } from '@/lib/postImportSession'
 import { cn, originalCreatedAtString } from '@/lib/utils'
 
 import type { FC } from 'react'
 
-import type { PostImportRow } from '@/lib/postImportTypes'
+import type { PostImportRow } from '@/lib/postImportSession'
 
 type Props = {
-    row:	      PostImportRow
+    row:              PostImportRow
     displayNumber?:   number
-    onEdit?:	      () => void
-    onRetry?:	      () => void
+    onEdit?:          () => void
+    onRetry?:         () => void
     onToggleSkip?:    (checked: boolean) => void
     rowMessages?:     string[]
     editDisabled?:    boolean
@@ -75,123 +71,129 @@ const PostImportRowSummary: FC<Props> = (
 
   return (
       <>
-	<div
-	    className={cn (
-		'hidden items-center gap-4 rounded-lg border p-4 md:grid',
-		'md:grid-cols-[4rem_5rem_minmax(0,1fr)_auto_auto]',
-		'transition-shadow hover:shadow-sm')}>
-	  <div className="space-y-1">
-	    <div className="text-sm font-medium">#{rowNumber}</div>
-	  </div>
-	  <PostImportThumbnailPreview
-	      url={String (row.attributes.thumbnailBase ?? '')}
-	      file={row.thumbnailFile}
-	      className="h-16 w-16"/>
-	  <div className="min-w-0 space-y-1">
-	    <div className="line-clamp-2 text-sm font-medium">
-	      {String (row.attributes.title ?? '')}
-	    </div>
-	    <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
-	      {row.url}
-	    </div>
-	    <PostImportTagLinks tags={row.displayTags}/>
-	    <div className="text-xs text-neutral-500 dark:text-neutral-400">
-	      {summaryDate (row)}
-	    </div>
-	    {showDuration && (
-		<div className="text-xs text-neutral-500 dark:text-neutral-400">
-		  動画時間 {duration}
-		</div>)}
-	    {warning && (
-		<div className="text-xs text-amber-700 dark:text-amber-200">
-		  {warning}
-		</div>)}
-	    <FieldError messages={rowMessages}/>
-	  </div>
-	  <div className="space-y-1">
-	    {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
-	  </div>
-	  <div className="flex justify-end">
-	    <div className="flex items-center gap-2">
-	      {skipControl}
-	      {showActions && editVisible && (
-		  <Button
-		      type="button"
-		      variant="outline"
-		      onClick={onEdit}
-		      disabled={editDisabled === true || !(editAllowed)}>
-		    編輯
-		  </Button>)}
-	      {showActions && retryAllowed && (
-		  <Button
-		      type="button"
-		      variant="outline"
-		      onClick={onRetry}
-		      disabled={retryDisabled === true}>
-		    再試行
-		  </Button>)}
-	    </div>
-	  </div>
-	</div>
+        <div
+            className={cn (
+                'hidden items-center gap-4 rounded-lg border p-4 md:grid',
+                'md:grid-cols-[4rem_5rem_minmax(0,1fr)_auto_auto]',
+                'transition-shadow hover:shadow-sm')}>
+          <div className="space-y-1">
+            <div className="text-sm font-medium">#{rowNumber}</div>
+          </div>
+          <PostImportThumbnailPreview
+              url={String (row.attributes.thumbnailBase ?? '')}
+              file={row.thumbnailFile}
+              className="h-16 w-16"/>
+          <div className="min-w-0 space-y-1">
+            <div className="line-clamp-2 text-sm font-medium">
+              {String (row.attributes.title ?? '')}
+            </div>
+            <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
+              {row.url}
+            </div>
+            {String (row.attributes.tags ?? '') && (
+                <div className="truncate text-xs text-neutral-500 dark:text-neutral-400">
+                  {String (row.attributes.tags ?? '')}
+                </div>)}
+            <div className="text-xs text-neutral-500 dark:text-neutral-400">
+              {summaryDate (row)}
+            </div>
+            {showDuration && (
+                <div className="text-xs text-neutral-500 dark:text-neutral-400">
+                  動画時間 {duration}
+                </div>)}
+            {warning && (
+                <div className="text-xs text-amber-700 dark:text-amber-200">
+                  {warning}
+                </div>)}
+            <FieldError messages={rowMessages}/>
+          </div>
+          <div className="space-y-1">
+            {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
+          </div>
+          <div className="flex justify-end">
+            <div className="flex items-center gap-2">
+              {skipControl}
+              {showActions && editVisible && (
+                  <Button
+                      type="button"
+                      variant="outline"
+                      onClick={onEdit}
+                      disabled={editDisabled === true || !(editAllowed)}>
+                    編輯
+                  </Button>)}
+              {showActions && retryAllowed && (
+                  <Button
+                      type="button"
+                      variant="outline"
+                      onClick={onRetry}
+                      disabled={retryDisabled === true}>
+                    再試行
+                  </Button>)}
+            </div>
+          </div>
+        </div>
 
-	<div
-	    className={cn (
-		'space-y-3 rounded-lg border p-4 md:hidden',
-		'transition-shadow hover:shadow-sm')}>
-	  <div className="text-sm font-medium">#{rowNumber}</div>
-	  <div className="flex items-start gap-3">
-	    <PostImportThumbnailPreview
-		url={String (row.attributes.thumbnailBase ?? '')}
-		file={row.thumbnailFile}
-		className="h-20 w-20 shrink-0"/>
-	    <div className="min-w-0 flex-1 space-y-2">
-	      <div className="line-clamp-2 text-sm font-medium">
-		{String (row.attributes.title ?? '')}
-	      </div>
-	      <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
-		{row.url}
-	      </div>
-	      <div className="flex flex-wrap gap-2">
-		{displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
-	      </div>
-	      <PostImportTagLinks tags={row.displayTags}/>
-	      <div className="text-xs text-neutral-500 dark:text-neutral-400">
-		{summaryDate (row)}
-	      </div>
-	      {showDuration && (
-		  <div className="text-xs text-neutral-500 dark:text-neutral-400">
-		    動画時間 {duration}
-		  </div>)}
-	      {warning && (
-		  <div className="text-xs text-amber-700 dark:text-amber-200">
-		    {warning}
-		  </div>)}
-	      <FieldError messages={rowMessages}/>
-	      {skipControl}
-	    </div>
-	  </div>
-	  {showActions && (editVisible || retryAllowed) && (
-	      <div className="flex flex-col gap-2 md:flex-row">
-		{editVisible && (
-		    <Button
-			type="button"
-			className="w-full md:w-auto"
-			variant="outline"
-			onClick={onEdit}
-			disabled={editDisabled === true || !(editAllowed)}>
-		      編輯
-		    </Button>)}
-		{retryAllowed && (
-		    <Button
-			type="button"
-			className="w-full md:w-auto"
-			variant="outline"
-			onClick={onRetry}
-			disabled={retryDisabled === true}>
-		      再試行
-		    </Button>)}
-	      </div>)}
-	</div>
+        <div
+            className={cn (
+                'space-y-3 rounded-lg border p-4 md:hidden',
+                'transition-shadow hover:shadow-sm')}>
+          <div className="text-sm font-medium">#{rowNumber}</div>
+          <div className="flex items-start gap-3">
+            <PostImportThumbnailPreview
+                url={String (row.attributes.thumbnailBase ?? '')}
+                file={row.thumbnailFile}
+                className="h-20 w-20 shrink-0"/>
+            <div className="min-w-0 flex-1 space-y-2">
+              <div className="line-clamp-2 text-sm font-medium">
+                {String (row.attributes.title ?? '')}
+              </div>
+              <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
+                {row.url}
+              </div>
+              <div className="flex flex-wrap gap-2">
+                {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
+              </div>
+              {String (row.attributes.tags ?? '') && (
+                  <div className="text-xs text-neutral-500 dark:text-neutral-400">
+                    {String (row.attributes.tags ?? '')}
+                  </div>)}
+              <div className="text-xs text-neutral-500 dark:text-neutral-400">
+                {summaryDate (row)}
+              </div>
+              {showDuration && (
+                  <div className="text-xs text-neutral-500 dark:text-neutral-400">
+                    動画時間 {duration}
+                  </div>)}
+              {warning && (
+                  <div className="text-xs text-amber-700 dark:text-amber-200">
+                    {warning}
+                  </div>)}
+              <FieldError messages={rowMessages}/>
+              {skipControl}
+            </div>
+          </div>
+          {showActions && (editVisible || retryAllowed) && (
+              <div className="flex flex-col gap-2 md:flex-row">
+                {editVisible && (
+                    <Button
+                        type="button"
+                        className="w-full md:w-auto"
+                        variant="outline"
+                        onClick={onEdit}
+                        disabled={editDisabled === true || !(editAllowed)}>
+                      編輯
+                    </Button>)}
+                {retryAllowed && (
+                    <Button
+                        type="button"
+                        className="w-full md:w-auto"
+                        variant="outline"
+                        onClick={onRetry}
+                        disabled={retryDisabled === true}>
+                      再試行
+                    </Button>)}
+              </div>)}
+        </div>
       </>)
 }
 

frontend/src/components/posts/import/PostImportTagLinks.tsx

@@ -1,36 +0,0 @@
-import TagLink from '@/components/TagLink'
-
-import type { FC } from 'react'
-
-import type { PostImportDisplayTag } from '@/lib/postImportTypes'
-
-type Props = {
-  tags: PostImportDisplayTag[] | undefined }
-
-const PostImportTagLinks: FC<Props> = ({ tags }) => {
-  if (tags == null || tags.length === 0)
-    return null
-
-  return (
-      <div className="flex flex-wrap text-xs gap-x-1">
-	{tags.map (tag => {
-	  const key = `${ tag.category }:${ tag.name }:${ tag.sectionLiterals?.join ('|') ?? '' }`
-	  return (
-	      <span key={key} className="inline-flex flex-nowrap items-baseline gap-1">
-		<TagLink
-		    tag={{
-			name: tag.name,
-			category: tag.category }}
-		    linkFlg={false}
-		    withWiki={false}
-		    withCount={false}/>
-		{tag.sectionLiterals?.map (literal => (
-		    <span key={literal} className="text-xs text-neutral-500 dark:text-neutral-400">
-		      {literal}
-		    </span>))}
-	      </span>)
-	})}
-      </div>)
-}
-
-export default PostImportTagLinks

frontend/src/components/posts/import/PostImportThumbnailPreview.test.tsx

@@ -1,8 +1,14 @@
-import { fireEvent, render, screen } from '@testing-library/react'
+import { render, screen, waitFor } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import PostImportThumbnailPreview from '@/components/posts/import/PostImportThumbnailPreview'
 
+const api = vi.hoisted (() => ({
+  apiGet: vi.fn (),
+}))
+
+vi.mock ('@/lib/api', () => api)
+
 describe ('PostImportThumbnailPreview', () => {
   beforeEach (() => {
     vi.clearAllMocks ()
@@ -10,50 +16,69 @@ describe ('PostImportThumbnailPreview', () => {
     globalThis.URL.revokeObjectURL = vi.fn ()
   })
 
-  it ('renders the remote URL directly without a backend proxy', () => {
-    render (
-	<PostImportThumbnailPreview
-	    url="https://example.com/thumbnail.jpg"
-	    className="h-10 w-10"/>)
+  it ('uses a backend-fetched blob URL instead of the external thumbnail URL directly', async () => {
+    api.apiGet.mockResolvedValueOnce (new Blob (['img'], { type: 'image/png' }))
 
-    expect (screen.getByRole ('img')).toHaveAttribute (
-	'src',
-	'https://example.com/thumbnail.jpg')
-    expect (screen.getByRole ('img')).toHaveAttribute (
-	'referrerpolicy',
-	'no-referrer')
+    render (
+        <PostImportThumbnailPreview
+            url="https://example.com/thumbnail.jpg"
+            className="h-10 w-10"/>)
+
+    await waitFor (() => {
+      expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:preview')
+    })
+    expect (screen.getByRole ('img')).not.toHaveAttribute (
+        'src',
+        'https://example.com/thumbnail.jpg')
+    expect (api.apiGet).toHaveBeenCalledWith ('/preview/thumbnail', {
+      params: { url: 'https://example.com/thumbnail.jpg' },
+      responseType: 'blob' })
   })
 
-  it ('shows the empty frame after the remote image fails', () => {
+  it ('does not render the unsafe URL directly when preview fetching fails', async () => {
+    api.apiGet.mockRejectedValueOnce (new Error ('unsafe'))
+
     const { container } = render (
-	<PostImportThumbnailPreview
-	    url="https://example.com/missing.jpg"
-	    className="h-10 w-10"/>)
+        <PostImportThumbnailPreview
+            url="http://127.0.0.1/private.png"
+            className="h-10 w-10"/>)
 
-    fireEvent.error (screen.getByRole ('img'))
-
-    expect (screen.queryByRole ('img')).toBeNull ()
+    await waitFor (() => {
+      expect (screen.queryByRole ('img')).toBeNull ()
+    })
+    expect (screen.queryByText ('サムネールを表示できません')).toBeNull ()
+    expect (screen.queryByText ('なし')).toBeNull ()
     expect (container.querySelector ('div.rounded.border.bg-muted')).not.toBeNull ()
     expect (container.textContent).toBe ('')
+    expect (screen.queryByRole ('img')).toBeNull ()
   })
 
-  it ('uses and revokes an object URL only when the remote URL is blank', () => {
-    const file = new File (['image'], 'thumbnail.png', { type: 'image/png' })
-    const { rerender, unmount } = render (
-	<PostImportThumbnailPreview url="" file={file} className="h-10 w-10"/>)
+  it ('revokes the old object URL when the source URL changes', async () => {
+    const createObjectUrlMock =
+        globalThis.URL.createObjectURL as unknown as ReturnType<typeof vi.fn>
+    createObjectUrlMock
+        .mockReturnValueOnce ('blob:first')
+        .mockReturnValueOnce ('blob:second')
+    api.apiGet
+        .mockResolvedValueOnce (new Blob (['first'], { type: 'image/png' }))
+        .mockResolvedValueOnce (new Blob (['second'], { type: 'image/png' }))
 
-    expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:preview')
+    const { rerender } = render (
+        <PostImportThumbnailPreview
+            url="https://example.com/first.jpg"
+            className="h-10 w-10"/>)
+    await waitFor (() => {
+      expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:first')
+    })
 
     rerender (
-	<PostImportThumbnailPreview
-	    url="https://example.com/remote.jpg"
-	    file={file}
-	    className="h-10 w-10"/>)
-    expect (screen.getByRole ('img')).toHaveAttribute (
-	'src',
-	'https://example.com/remote.jpg')
+        <PostImportThumbnailPreview
+            url="https://example.com/second.jpg"
+            className="h-10 w-10"/>)
 
-    unmount ()
-    expect (globalThis.URL.revokeObjectURL).toHaveBeenCalledWith ('blob:preview')
+    await waitFor (() => {
+      expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:second')
+    })
+    expect (globalThis.URL.revokeObjectURL).toHaveBeenCalledWith ('blob:first')
   })
 })

frontend/src/components/posts/import/postImportRowStatus.test.ts

@@ -16,14 +16,14 @@ describe ('displayPostImportStatus', () => {
       skipReason: 'manual' }))).toBe ('skipped')
   })
 
-  it ('distinguishes validation, failure, and created states', () => {
+  it ('does not expose validation, failure, or created states as badges', () => {
     expect (displayPostImportStatus (buildPostImportRow ({
       status: 'error',
-      validationErrors: { title: ['invalid'] } }))).toBe ('error')
+      validationErrors: { title: ['invalid'] } }))).toBeNull ()
     expect (displayPostImportStatus (buildPostImportRow ({
-      importStatus: 'failed' }))).toBe ('failed')
+      importStatus: 'failed' }))).toBeNull ()
     expect (displayPostImportStatus (buildPostImportRow ({
       importStatus: 'created',
-      createdPostId: 3 }))).toBe ('created')
+      createdPostId: 3 }))).toBeNull ()
   })
 })

frontend/src/components/posts/import/postImportRowStatus.ts

@@ -1,4 +1,4 @@
-import type { PostImportRow } from '@/lib/postImportTypes'
+import type { PostImportRow } from '@/lib/postImportSession'
 
 export type PostImportDisplayStatus =
     'ready'

frontend/src/components/ui/dialog.tsx

@@ -1,10 +1,10 @@
-'use client'
+"use client"
 
-import * as DialogPrimitive from '@radix-ui/react-dialog'
-import { X } from 'lucide-react'
-import * as React from 'react'
+import * as React from "react"
+import * as DialogPrimitive from "@radix-ui/react-dialog"
+import { X } from "lucide-react"
 
-import { cn } from '@/lib/utils'
+import { cn } from "@/lib/utils"
 
 const Dialog = DialogPrimitive.Root
 
@@ -15,109 +15,111 @@ const DialogPortal = DialogPrimitive.Portal
 const DialogClose = DialogPrimitive.Close
 
 const DialogOverlay = React.forwardRef<
-    React.ElementRef<typeof DialogPrimitive.Overlay>,
-    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Overlay>
->(
-    ({ className, ...props }, ref) => (
-	<DialogPrimitive.Overlay
-	    ref={ref}
-	    className={cn (
-		'fixed inset-0 z-50 bg-black/80',
-		'data-[state=open]:animate-in data-[state=closed]:animate-out',
-		'data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0',
-		className)}
-	    {...props}/>))
+  React.ElementRef<typeof DialogPrimitive.Overlay>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Overlay>
+>(({ className, ...props }, ref) => (
+  <DialogPrimitive.Overlay
+    ref={ref}
+    className={cn(
+      "fixed inset-0 z-50 bg-black/80 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0",
+      className)}
+    {...props}
+  />))
 DialogOverlay.displayName = DialogPrimitive.Overlay.displayName
 
 const DialogContent = React.forwardRef<
-    React.ElementRef<typeof DialogPrimitive.Content>,
-    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Content>
->(
-    ({ className, children, ...props }, ref) => (
-	<DialogPortal>
-	  <DialogOverlay />
-	  <DialogPrimitive.Content
-	      ref={ref}
-	      className={cn (
-		  'fixed left-[50%] top-[50%] z-50 grid w-[calc(100%-2rem)] max-w-lg',
-		  'translate-x-[-50%] translate-y-[-50%]',
-		  'gap-5 rounded-2xl border border-border',
-		  'bg-background p-6 text-foreground shadow-2xl',
-		  'duration-200',
-		  'data-[state=open]:animate-in data-[state=closed]:animate-out',
-		  'data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0',
-		  'data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95',
-		  className)}
-	      {...props}>
-	    {children}
+  React.ElementRef<typeof DialogPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Content>
+>(({ className, children, ...props }, ref) => (
+  <DialogPortal>
+    <DialogOverlay />
+    <DialogPrimitive.Content
+      ref={ref}
+      className={cn (
+	  'fixed left-[50%] top-[50%] z-50 grid w-[calc(100%-2rem)] max-w-lg',
+	  'translate-x-[-50%] translate-y-[-50%]',
+	  'gap-5 rounded-2xl border border-border',
+	  'bg-background p-6 text-foreground shadow-2xl',
+	  'duration-200',
+	  'data-[state=open]:animate-in data-[state=closed]:animate-out',
+	  'data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0',
+	  'data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95',
+	  className)}
+      {...props}
+    >
+      {children}
 
-	    <DialogPrimitive.Close
-		className={cn (
-		    'absolute left-4 top-4 rounded-full p-1',
-		    'text-slate-500 transition-colors',
-		    'hover:bg-slate-200 hover:text-slate-900',
-		    'dark:text-slate-400 dark:hover:bg-slate-700 dark:hover:text-slate-50',
-		    'focus:outline-none focus:ring-2 focus:ring-slate-400')}>
-	      <X className="h-4 w-4"/>
-	      <span className="sr-only">閉ぢる</span>
-	    </DialogPrimitive.Close>
-	  </DialogPrimitive.Content>
-	</DialogPortal>))
+      <DialogPrimitive.Close
+	  className={cn (
+	      'absolute left-4 top-4 rounded-full p-1',
+	      'text-slate-500 transition-colors',
+	      'hover:bg-slate-200 hover:text-slate-900',
+	      'dark:text-slate-400 dark:hover:bg-slate-700 dark:hover:text-slate-50',
+	      'focus:outline-none focus:ring-2 focus:ring-slate-400')}>
+	<X className="h-4 w-4"/>
+	<span className="sr-only">閉ぢる</span>
+      </DialogPrimitive.Close>
+    </DialogPrimitive.Content>
+  </DialogPortal>))
 DialogContent.displayName = DialogPrimitive.Content.displayName
 
-const DialogHeader = (
-    { className, ...props }: React.HTMLAttributes<HTMLDivElement>,
-) => (
-    <div
-	className={cn (
-	    'flex flex-col space-y-1.5 text-center md:text-left',
-	    className)}
-	{...props}/>)
-DialogHeader.displayName = 'DialogHeader'
+const DialogHeader = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) => (
+  <div
+    className={cn(
+      "flex flex-col space-y-1.5 text-center md:text-left",
+      className)}
+    {...props}
+  />)
+DialogHeader.displayName = "DialogHeader"
 
-const DialogFooter = (
-    { className, ...props }: React.HTMLAttributes<HTMLDivElement>,
-) => (
-    <div
-	className={cn (
-	    'flex flex-col-reverse md:flex-row md:justify-end md:space-x-2',
-	    className)}
-	{...props}/>)
-DialogFooter.displayName = 'DialogFooter'
+const DialogFooter = ({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) => (
+  <div
+    className={cn(
+      "flex flex-col-reverse md:flex-row md:justify-end md:space-x-2",
+      className)}
+    {...props}
+  />)
+DialogFooter.displayName = "DialogFooter"
 
 const DialogTitle = React.forwardRef<
-    React.ElementRef<typeof DialogPrimitive.Title>,
-    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Title>
->(
-    ({ className, ...props }, ref) => (
-	<DialogPrimitive.Title
-	    ref={ref}
-	    className={cn (
-		'text-lg font-semibold leading-none tracking-tight',
-		className)}
-	    {...props}/>))
+  React.ElementRef<typeof DialogPrimitive.Title>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Title>
+>(({ className, ...props }, ref) => (
+  <DialogPrimitive.Title
+    ref={ref}
+    className={cn(
+      "text-lg font-semibold leading-none tracking-tight",
+      className)}
+    {...props}
+  />))
 DialogTitle.displayName = DialogPrimitive.Title.displayName
 
 const DialogDescription = React.forwardRef<
-    React.ElementRef<typeof DialogPrimitive.Description>,
-    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Description>
->(
-    ({ className, ...props }, ref) => (
-	<DialogPrimitive.Description
-	    ref={ref}
-	    className={cn ('text-sm text-muted-foreground', className)}
-	    {...props}/>))
+  React.ElementRef<typeof DialogPrimitive.Description>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Description>
+>(({ className, ...props }, ref) => (
+  <DialogPrimitive.Description
+    ref={ref}
+    className={cn("text-sm text-muted-foreground", className)}
+    {...props}
+  />))
 DialogDescription.displayName = DialogPrimitive.Description.displayName
 
 export {
-    Dialog,
-    DialogPortal,
-    DialogOverlay,
-    DialogClose,
-    DialogTrigger,
-    DialogContent,
-    DialogHeader,
-    DialogFooter,
-    DialogTitle,
-    DialogDescription,
+  Dialog,
+  DialogPortal,
+  DialogOverlay,
+  DialogClose,
+  DialogTrigger,
+  DialogContent,
+  DialogHeader,
+  DialogFooter,
+  DialogTitle,
+  DialogDescription,
 }

frontend/src/lib/postImportRows.test.ts

@@ -16,7 +16,7 @@ import { creatableImportRows,
 	 resultRowMessages,
 	 resultSummaryCounts,
 	 retryImportRow,
-	 reviewSummaryCounts } from '@/lib/postImportRows'
+	 reviewSummaryCounts } from '@/lib/postImportSession'
 import { buildPostImportRow } from '@/test/postImportFactories'
 
 describe ('post import row state', () => {
@@ -274,7 +274,6 @@ describe ('post import row state', () => {
           thumbnailBase: '',
           originalCreatedFrom: '',
           originalCreatedBefore: '',
-          duration: '2',
           tags: 'edited-tag',
           parentPostIds: '' },
         true)

frontend/src/lib/postImportRows.ts

@@ -68,10 +68,6 @@ export const validatableImportRows = (rows: PostImportRow[]): PostImportRow[] =>
 const buildResetSnapshot = (row: PostImportRow) => ({
     url: row.url,
     attributes: { ...row.attributes },
-    displayTags: row.displayTags?.map (tag => ({
-	name: tag.name,
-	category: tag.category,
-	sectionLiterals: tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })) ?? [],
     provenance: { ...row.provenance },
     tagSources: {
 	automatic: row.tagSources?.automatic ?? '',
@@ -226,6 +222,11 @@ export const buildNextEditedRow = (
 	    ? 'manual'
 	    : (editingRow.provenance[field] ?? 'automatic')
     })
+    if (nextProvenance.duration === 'manual')
+      {
+	nextAttributes.videoMs = ''
+	nextProvenance.videoMs = 'manual'
+      }
     nextAttributes.tags = draft.tags
     if (isManualChange (editingRow.attributes.tags, draft.tags))
       {
@@ -242,11 +243,6 @@ export const buildNextEditedRow = (
 	...editingRow,
 	url: draft.url,
 	attributes: nextAttributes,
-	displayTags:
-	    editingRow.displayTags?.map (tag => ({
-		name: tag.name,
-		category: tag.category,
-		sectionLiterals: tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })),
 	thumbnailFile: draft.thumbnailFile,
 	provenance: {
 	    ...nextProvenance,
@@ -320,12 +316,6 @@ export const mergeValidatedImportRows = (
           ...previous,
           url: row.url,
           attributes: row.attributes,
-          displayTags:
-              row.displayTags?.map (tag => ({
-                  name: tag.name,
-                  category: tag.category,
-                  sectionLiterals:
-                      tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })),
           provenance: row.provenance,
           tagSources: row.tagSources,
           skipReason: row.skipReason,

frontend/src/lib/postImportSession.ts

@@ -0,0 +1,4 @@
+export * from '@/lib/postImportTypes'
+export * from '@/lib/postImportStorage'
+export * from '@/lib/postImportSourceValidation'
+export * from '@/lib/postImportRows'

frontend/src/lib/postImportSourceValidation.test.ts

@@ -1,9 +1,6 @@
 import { describe, expect, it } from 'vitest'
 
-import {
-    countImportSourceLines,
-    validateImportSource,
-} from '@/lib/postImportSourceValidation'
+import { countImportSourceLines, validateImportSource } from '@/lib/postImportSession'
 
 describe ('post import source validation', () => {
   it ('counts trimmed non-empty CRLF and LF rows', () => {

frontend/src/lib/postImportSourceValidation.ts

@@ -12,14 +12,23 @@ const bytesize = (value: string): number =>
     new TextEncoder ().encode (value).length
 
 
-const parseImportUrl = (value: string): URL | null => {
+const normaliseImportUrl = (value: string): string | null => {
     const trimmed = value.trim ()
     if (!(trimmed))
       return null
 
     try
     {
-      return new URL (trimmed)
+      const url = new URL (trimmed)
+      if (!(url.protocol === 'http:' || url.protocol === 'https:'))
+        return null
+      if (!(url.host))
+        return null
+
+      url.hostname = url.hostname.toLowerCase ()
+      if (url.pathname.endsWith ('/'))
+        url.pathname = url.pathname.replace (/\/+$/, '')
+      return url.toString ()
     }
     catch
     {
@@ -28,23 +37,12 @@ const parseImportUrl = (value: string): URL | null => {
 }
 
 
-const normaliseImportUrl = (url: URL): string => {
-  url.hostname = url.hostname.toLowerCase ()
-  if (url.pathname.endsWith ('/'))
-    url.pathname = url.pathname.replace (/\/+$/, '')
-  return url.toString ()
-}
-
-
-export const extractImportSourceUrls = (source: string): string[] =>
+export const countImportSourceLines = (source: string): number =>
     source
         .split (/\r\n|\n|\r/)
         .map (line => line.trim ())
         .filter (line => line !== '')
-
-
-export const countImportSourceLines = (source: string): number =>
-    extractImportSourceUrls (source).length
+        .length
 
 
 export const validateImportSource = (
@@ -63,6 +61,7 @@ export const validateImportSource = (
       ++count
       const sourceRow = index + 1
       const displayUrl = truncateUrl (value)
+      const normalised = normaliseImportUrl (value)
       if (count > MAX_ROWS)
         {
           issues.push ({
@@ -71,6 +70,14 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
+      if (!(value.startsWith ('http://') || value.startsWith ('https://')))
+        {
+          issues.push ({
+              sourceRow,
+              message: 'HTTP または HTTPS の URL ではありません．',
+              url: displayUrl })
+          return
+        }
       if (bytesize (value) > MAX_URL_BYTES)
         {
           issues.push ({
@@ -79,8 +86,7 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
-      const parsed = parseImportUrl (value)
-      if (parsed == null)
+      if (normalised == null)
         {
           issues.push ({
               sourceRow,
@@ -88,23 +94,6 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
-      if (!(parsed.protocol === 'http:' || parsed.protocol === 'https:'))
-        {
-          issues.push ({
-              sourceRow,
-              message: 'HTTP または HTTPS の URL ではありません．',
-              url: displayUrl })
-          return
-        }
-      if (!(parsed.host))
-        {
-          issues.push ({
-              sourceRow,
-              message: 'URL の形式が不正です．',
-              url: displayUrl })
-          return
-        }
-      const normalised = normaliseImportUrl (parsed)
       const duplicateRow = seen.get (normalised)
       if (duplicateRow != null)
         {

frontend/src/lib/postImportStorage.test.ts

@@ -1,31 +1,124 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
-import {
-    clearPostImportSourceDraft,
-    loadPostImportSourceDraft,
-    savePostImportSourceDraft,
-} from '@/lib/postImportStorage'
+import { cleanupExpiredPostImportSessions,
+	 clearPostImportSourceDraft,
+	 loadPostImportSession,
+	 loadPostImportSourceDraft,
+	 savePostImportSession,
+	 savePostImportSourceDraft } from '@/lib/postImportSession'
+import { buildPostImportRow } from '@/test/postImportFactories'
 
-describe ('post import source draft storage', () => {
+describe ('post import storage', () => {
   beforeEach (() => {
     sessionStorage.clear ()
-    vi.restoreAllMocks ()
+    vi.useRealTimers ()
   })
 
-  it ('round-trips and clears the URL list source draft', () => {
+  it ('round-trips a valid session and source draft', () => {
+    const row = buildPostImportRow ({
+      attributes: { duration: '2.5' },
+      recoverable: true,
+      importStatus: 'pending',
+      validationErrors: { title: ['invalid'] } })
+    const skipped = buildPostImportRow ({
+      importStatus: 'skipped',
+      skipReason: 'existing',
+      existingPostId: 10 })
+    const manual = buildPostImportRow ({
+      sourceRow: 3,
+      skipReason: 'manual' })
+
+    expect (savePostImportSession ({
+      source: skipped.url,
+      rows: [row, skipped, manual],
+      repairMode: 'all' })).toBe (true)
+    expect (loadPostImportSession ()).toMatchObject ({
+      version: 2,
+      source: skipped.url,
+      rows: [{
+	attributes: { duration: '2.5' },
+	recoverable: true,
+	importStatus: 'pending' },
+	      {
+	importStatus: 'skipped',
+	skipReason: 'existing',
+	existingPostId: 10 },
+	      {
+	skipReason: 'manual' }] })
+
     expect (savePostImportSourceDraft ('https://example.com')).toBe (true)
-    expect (loadPostImportSourceDraft ()).toEqual ({
-	source: 'https://example.com' })
-
+    expect (loadPostImportSourceDraft ()).toEqual ({ source: 'https://example.com' })
     clearPostImportSourceDraft ()
-
     expect (loadPostImportSourceDraft ()).toEqual ({ source: '' })
   })
 
-  it ('ignores malformed stored drafts', () => {
-    sessionStorage.setItem ('post-import-source-draft', '{')
+  it ('rejects inconsistent post IDs and terminal statuses', () => {
+    const session = {
+      version: 2,
+      savedAt: new Date ().toISOString (),
+      source: '',
+      repairMode: 'all',
+      rows: [buildPostImportRow ()] }
+    const invalidRows = [
+      { ...session.rows[0], skipReason: 'existing', existingPostId: undefined },
+      { ...session.rows[0], existingPostId: 2, skipReason: undefined },
+      { ...session.rows[0], importStatus: 'created', createdPostId: undefined },
+      { ...session.rows[0], importStatus: 'failed', createdPostId: 3 },
+      { ...session.rows[0], importStatus: 'created', recoverable: true },
+      { ...session.rows[0], importStatus: 'skipped', recoverable: true },
+      { ...session.rows[0], recoverable: true }]
 
-    expect (loadPostImportSourceDraft ()).toEqual ({ source: '' })
+    for (const row of invalidRows)
+      {
+	sessionStorage.setItem ('post-import-session:current', JSON.stringify ({
+	  ...session,
+	  rows: [row] }))
+	expect (loadPostImportSession ()).toBeNull ()
+	sessionStorage.clear ()
+      }
+  })
+
+  it ('rejects invalid attribute, provenance, tag-source, and snapshot data', () => {
+    const row = buildPostImportRow ()
+    const invalidRows = [
+      { ...row, attributes: { title: [] } },
+      { ...row, attributes: { unknown: 'value' } },
+      { ...row, provenance: { title: 'mapped' } },
+      { ...row, tagSources: { mapped: 'tag' } },
+      { ...row, resetSnapshot: { ...row.resetSnapshot,
+	fieldWarnings: { title: 'warning' } } }]
+
+    invalidRows.forEach (invalidRow => {
+      sessionStorage.setItem ('post-import-session:current', JSON.stringify ({
+	version: 2,
+	savedAt: new Date ().toISOString (),
+	source: '',
+	rows: [invalidRow],
+	repairMode: 'all' }))
+      expect (loadPostImportSession ()).toBeNull ()
+      sessionStorage.clear ()
+    })
+  })
+
+  it ('keeps only the current fixed-key session and removes legacy prefixed entries', () => {
+    const current = {
+      version: 2,
+      savedAt: new Date ().toISOString (),
+      source: '',
+      rows: [buildPostImportRow ()],
+      repairMode: 'all' }
+    const expired = {
+      ...current,
+      savedAt: new Date (Date.now () - 25 * 60 * 60 * 1000).toISOString () }
+    sessionStorage.setItem ('post-import-session:current', JSON.stringify (current))
+    sessionStorage.setItem ('post-import-session:expired', JSON.stringify (expired))
+    sessionStorage.setItem ('post-import-session:malformed', '{')
+
+    cleanupExpiredPostImportSessions ()
+
+    expect (sessionStorage.getItem ('post-import-session:current')).not.toBeNull ()
+    expect (sessionStorage.getItem ('post-import-session:expired')).toBeNull ()
+    expect (sessionStorage.getItem ('post-import-session:malformed')).toBeNull ()
   })
 
   it ('reports storage access failures without throwing', () => {

frontend/src/lib/postImportStorage.ts

@@ -1,24 +1,123 @@
-import type { StorageErrorHandler } from '@/lib/postImportTypes'
+import type { PostImportOrigin,
+	      PostImportExistingPost,
+	      PostImportResetSnapshot,
+	      PostImportRow,
+	      PostImportSession,
+	      PostImportStatus,
+	      PostImportSkipReason,
+	      StorageErrorHandler } from '@/lib/postImportTypes'
 
+const SESSION_VERSION = 3
+const SESSION_PREFIX = 'post-import-session:'
 const SOURCE_DRAFT_KEY = 'post-import-source-draft'
+const SESSION_MAX_AGE_MS = 24 * 60 * 60 * 1000
+const MAX_SESSION_JSON_BYTES = 262_144
+const MAX_SESSION_ROWS = 100
+const MAX_SOURCE_BYTES = 262_144
+const SESSION_ID_PATTERN =
+    /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
+const ATTRIBUTE_KEYS = [
+    'title',
+    'thumbnailBase',
+    'originalCreatedFrom',
+    'originalCreatedBefore',
+    'duration',
+    'videoMs',
+    'tags',
+    'parentPostIds'] as const
+const PROVENANCE_KEYS = [...ATTRIBUTE_KEYS, 'url'] as const
+const TAG_SOURCE_KEYS = ['automatic', 'manual'] as const
+const WARNING_KEYS = [...ATTRIBUTE_KEYS, 'url'] as const
+const ROW_KEYS = [
+    'sourceRow',
+    'url',
+    'attributes',
+    'fieldWarnings',
+    'baseWarnings',
+    'validationErrors',
+    'importErrors',
+    'provenance',
+    'tagSources',
+    'status',
+    'skipReason',
+    'existingPostId',
+    'existingPost',
+    'metadataUrl',
+    'resetSnapshot',
+    'createdPostId',
+    'importStatus',
+    'recoverable'] as const
+const SESSION_KEYS = [
+    'version',
+    'expiresAt',
+    'source',
+    'rows',
+    'repairMode'] as const
+const textEncoder = new TextEncoder ()
+
+
+const isPlainObject = (value: unknown): value is Record<string, unknown> =>
+    typeof value === 'object' && value != null && !(Array.isArray (value))
+
+const byteLength = (value: string): number =>
+    textEncoder.encode (value).byteLength
+
+
+export const validatePostImportSessionId = (value: unknown): string | null => {
+    if (typeof value !== 'string')
+      return null
+    if (value.length > 36 || !(SESSION_ID_PATTERN.test (value)))
+      return null
+
+    return value.toLowerCase ()
+}
+
+
+const generateUuidV4FromRandomValues = (): string => {
+    const bytes = new Uint8Array (16)
+    crypto.getRandomValues (bytes)
+    bytes[6] = (bytes[6] & 0x0f) | 0x40
+    bytes[8] = (bytes[8] & 0x3f) | 0x80
+
+    const hex = Array.from (
+	bytes,
+	byte => byte.toString (16).padStart (2, '0'))
+    return [
+	hex.slice (0, 4).join (''),
+	hex.slice (4, 6).join (''),
+	hex.slice (6, 8).join (''),
+	hex.slice (8, 10).join (''),
+	hex.slice (10, 16).join ('')].join ('-')
+}
+
+
+export const generatePostImportSessionId = (): string => {
+    if (typeof crypto.randomUUID === 'function')
+      return crypto.randomUUID ()
+
+    return generateUuidV4FromRandomValues ()
+}
+
+
+const sessionKey = (sessionId: string): string => `${ SESSION_PREFIX }${ sessionId }`
 
 
 const readStorage = (
     key:       string,
     onError?:  StorageErrorHandler,
 ): string | null => {
-  if (typeof window === 'undefined')
-    return null
+    if (typeof window === 'undefined')
+      return null
 
-  try
-  {
-    return sessionStorage.getItem (key)
-  }
-  catch
-  {
-    onError?.('保存済みデータを読み込めませんでした．')
-    return null
-  }
+    try
+    {
+      return sessionStorage.getItem (key)
+    }
+    catch
+    {
+      onError?.('保存済みデータを読み込めませんでした．')
+      return null
+    }
 }
 
 
@@ -27,19 +126,19 @@ const writeStorage = (
     value:     string,
     onError?:  StorageErrorHandler,
 ): boolean => {
-  if (typeof window === 'undefined')
-    return false
+    if (typeof window === 'undefined')
+      return false
 
-  try
-  {
-    sessionStorage.setItem (key, value)
-    return true
-  }
-  catch
-  {
-    onError?.('ブラウザへ保存できませんでした．')
-    return false
-  }
+    try
+    {
+      sessionStorage.setItem (key, value)
+      return true
+    }
+    catch
+    {
+      onError?.('ブラウザへ保存できませんでした．')
+      return false
+    }
 }
 
 
@@ -47,36 +146,450 @@ const removeStorage = (
     key:       string,
     onError?:  StorageErrorHandler,
 ) => {
-  if (typeof window === 'undefined')
-    return
+    if (typeof window === 'undefined')
+      return
 
-  try
-  {
-    sessionStorage.removeItem (key)
-  }
-  catch
-  {
-    onError?.('保存済みデータを削除できませんでした．')
-  }
+    try
+    {
+      sessionStorage.removeItem (key)
+    }
+    catch
+    {
+      onError?.('保存済みデータを削除できませんでした．')
+    }
+}
+
+
+const ensureStringListRecord = (value: unknown): Record<string, string[]> | null => {
+    if (!(isPlainObject (value)))
+      return null
+
+    const result: Record<string, string[]> = { }
+    for (const [key, entry] of Object.entries (value))
+      {
+        if (!(Array.isArray (entry)) || !(entry.every (item => typeof item === 'string')))
+          return null
+        result[key] = entry
+      }
+    return result
+}
+
+
+const isValidStatus = (
+    value: unknown,
+): value is PostImportRow['status'] =>
+    value === 'pending'
+    || value === 'ready'
+    || value === 'warning'
+    || value === 'error'
+
+
+const isValidImportStatus = (
+    value: unknown,
+): value is PostImportStatus =>
+    value === 'pending'
+    || value === 'created'
+    || value === 'skipped'
+    || value === 'failed'
+
+
+const isValidOrigin = (
+    value: unknown,
+): value is PostImportOrigin =>
+    value === 'automatic' || value === 'manual'
+
+
+const isValidSkipReason = (
+    value: unknown,
+): value is PostImportSkipReason =>
+    value === 'existing' || value === 'manual'
+
+const isPositiveInteger = (value: unknown): value is number =>
+    Number.isInteger (value) && Number (value) > 0
+
+const hasOnlyKeys = (
+    value:        Record<string, unknown>,
+    allowedKeys:  readonly string[],
+): boolean =>
+    Object.keys (value).every (key => allowedKeys.includes (key))
+
+const sanitiseResetSnapshot = (value: unknown): PostImportResetSnapshot | null => {
+    if (!(isPlainObject (value)))
+      return null
+    if (!(hasOnlyKeys (value, ['url',
+			       'attributes',
+			       'provenance',
+			       'tagSources',
+			       'fieldWarnings',
+			       'baseWarnings',
+			       'metadataUrl'])))
+      return null
+    if (typeof value.url !== 'string')
+      return null
+    if (!(isPlainObject (value.attributes)))
+      return null
+    if (!(hasOnlyKeys (value.attributes, ATTRIBUTE_KEYS)))
+      return null
+    if (!(Object.values (value.attributes).every (entry =>
+        typeof entry === 'string' || typeof entry === 'number')))
+      return null
+    if (!(isPlainObject (value.provenance)))
+      return null
+    if (!(hasOnlyKeys (value.provenance, PROVENANCE_KEYS)))
+      return null
+    if (!(Object.values (value.provenance).every (origin => isValidOrigin (origin))))
+      return null
+    if (!(isPlainObject (value.tagSources)))
+      return null
+    if (!(hasOnlyKeys (value.tagSources, TAG_SOURCE_KEYS)))
+      return null
+    if (!(Object.values (value.tagSources).every (entry => typeof entry === 'string')))
+      return null
+    const fieldWarnings = ensureStringListRecord (value.fieldWarnings)
+    if (fieldWarnings == null)
+      return null
+    if (!(hasOnlyKeys (fieldWarnings, WARNING_KEYS)))
+      return null
+    if (!(Array.isArray (value.baseWarnings))
+        || !(value.baseWarnings.every (warning => typeof warning === 'string')))
+      return null
+    if (value.metadataUrl != null && typeof value.metadataUrl !== 'string')
+      return null
+
+    return {
+        url: value.url,
+        attributes: value.attributes as Record<string, string | number>,
+        provenance: value.provenance as Record<string, PostImportOrigin>,
+        tagSources: value.tagSources as Record<PostImportOrigin, string>,
+        fieldWarnings,
+        baseWarnings: value.baseWarnings,
+        metadataUrl: value.metadataUrl as string | undefined }
+}
+
+const sanitiseExistingPost = (value: unknown): PostImportExistingPost | undefined => {
+    if (value == null)
+      return undefined
+    if (!(isPlainObject (value)))
+      return undefined
+    if (!(isPositiveInteger (value.id)))
+      return undefined
+    if (typeof value.title !== 'string' || typeof value.url !== 'string')
+      return undefined
+    if (value.thumbnailUrl != null && typeof value.thumbnailUrl !== 'string')
+      return undefined
+
+    return {
+        id: Number (value.id),
+        title: value.title,
+        url: value.url,
+        thumbnailUrl: value.thumbnailUrl as string | undefined }
+}
+
+const recalculateThumbnailWarning = (row: PostImportRow): PostImportRow => {
+    const others = (row.fieldWarnings.thumbnailBase ?? []).filter (
+	key => key !== 'サムネールなし')
+    const thumbnailBasePresent =
+	typeof row.attributes.thumbnailBase === 'string'
+	&& row.attributes.thumbnailBase.trim () !== ''
+
+    return {
+        ...row,
+        fieldWarnings: {
+	    ...row.fieldWarnings,
+	    thumbnailBase:
+		thumbnailBasePresent
+		? others
+		: [...new Set ([...others, 'サムネールなし'])] } }
+}
+
+const serialiseExistingPost = (value: PostImportExistingPost | undefined) =>
+    value == null
+    ? undefined
+    : {
+	 id: value.id,
+	 title: value.title,
+	 url: value.url,
+	 thumbnailUrl: value.thumbnailUrl }
+
+const serialiseResetSnapshot = (value: PostImportResetSnapshot) => ({
+    url: value.url,
+    attributes: Object.fromEntries (
+	Object.entries (value.attributes).map (([key, entry]) => [key, entry])),
+    provenance: Object.fromEntries (
+	Object.entries (value.provenance).map (([key, entry]) => [key, entry])),
+    tagSources: {
+	automatic: value.tagSources.automatic,
+	manual: value.tagSources.manual },
+    fieldWarnings: Object.fromEntries (
+	Object.entries (value.fieldWarnings).map (([key, entry]) => [key, [...entry]])),
+    baseWarnings: [...value.baseWarnings],
+    metadataUrl: value.metadataUrl })
+
+export const serialisePostImportRow = (row: PostImportRow) => {
+    const thumbnailBaseWarnings = (() => {
+      const others = (row.fieldWarnings.thumbnailBase ?? []).filter (
+	  message => message !== 'サムネールなし')
+      const thumbnailBasePresent =
+	  typeof row.attributes.thumbnailBase === 'string'
+	  && row.attributes.thumbnailBase.trim () !== ''
+      return thumbnailBasePresent
+	  ? others
+	  : [...new Set ([...others, 'サムネールなし'])]
+    }) ()
+
+    return {
+	sourceRow: row.sourceRow,
+	url: row.url,
+	attributes: Object.fromEntries (
+	    Object.entries (row.attributes).map (([key, entry]) => [key, entry])),
+	fieldWarnings: Object.fromEntries (
+	    Object.entries ({
+		...row.fieldWarnings,
+		thumbnailBase: thumbnailBaseWarnings }).map (([key, entry]) => [key, [...entry]])),
+	baseWarnings: [...row.baseWarnings],
+	validationErrors: Object.fromEntries (
+	    Object.entries (row.validationErrors).map (([key, entry]) => [key, [...entry]])),
+	importErrors:
+	    row.importErrors == null
+	    ? undefined
+	    : Object.fromEntries (
+		Object.entries (row.importErrors).map (([key, entry]) => [key, [...entry]])),
+	provenance: Object.fromEntries (
+	    Object.entries (row.provenance).map (([key, entry]) => [key, entry])),
+	tagSources:
+	    row.tagSources == null
+	    ? undefined
+	    : {
+		automatic: row.tagSources.automatic,
+		manual: row.tagSources.manual },
+	status: row.status,
+	skipReason: row.skipReason,
+	existingPostId: row.existingPostId,
+	existingPost: serialiseExistingPost (row.existingPost),
+	metadataUrl: row.metadataUrl,
+	resetSnapshot: serialiseResetSnapshot (row.resetSnapshot),
+	createdPostId: row.createdPostId,
+	importStatus: row.importStatus,
+	recoverable: row.recoverable }
+}
+
+export const serialisePostImportRows = (rows: PostImportRow[]) =>
+    rows.map (row => serialisePostImportRow (row))
+
+export const serialisedPostImportRowsEqual = (
+    left:  PostImportRow[],
+    right: PostImportRow[],
+): boolean =>
+    JSON.stringify (serialisePostImportRows (left))
+    === JSON.stringify (serialisePostImportRows (right))
+
+
+const sanitiseRow = (value: unknown): PostImportRow | null => {
+    if (!(isPlainObject (value)))
+      return null
+    if (!(hasOnlyKeys (value, ROW_KEYS)))
+      return null
+    if (!(Number.isInteger (value.sourceRow)) || Number (value.sourceRow) <= 0)
+      return null
+    if (typeof value.url !== 'string')
+      return null
+    if (byteLength (value.url) > 20_480)
+      return null
+    if (!(isPlainObject (value.attributes)))
+      return null
+    if (!(isPlainObject (value.provenance)))
+      return null
+    if (!(isValidStatus (value.status)))
+      return null
+    if (value.importStatus != null && !(isValidImportStatus (value.importStatus)))
+      return null
+    if (value.skipReason != null && !(isValidSkipReason (value.skipReason)))
+      return null
+    if (value.recoverable != null && value.recoverable !== true)
+      return null
+    if (value.skipReason === 'existing' && !(isPositiveInteger (value.existingPostId)))
+      return null
+    if (value.skipReason !== 'existing' && value.existingPostId != null)
+      return null
+    if (value.importStatus === 'created' && !(isPositiveInteger (value.createdPostId)))
+      return null
+    if (value.importStatus !== 'created' && value.createdPostId != null)
+      return null
+    if (value.recoverable === true
+        && value.importStatus !== 'failed'
+        && value.importStatus !== 'pending')
+      return null
+    if ((value.importStatus === 'created' || value.importStatus === 'skipped')
+        && value.recoverable != null)
+      return null
+
+    const validationErrors = ensureStringListRecord (value.validationErrors)
+    const fieldWarnings = ensureStringListRecord (value.fieldWarnings)
+    const resetSnapshot = sanitiseResetSnapshot (value.resetSnapshot)
+    if (validationErrors == null || fieldWarnings == null)
+      return null
+    if (resetSnapshot == null)
+      return null
+
+    const importErrors =
+        value.importErrors == null
+        ? undefined
+        : ensureStringListRecord (value.importErrors)
+    if (importErrors === null)
+      return null
+    if (!(Array.isArray (value.baseWarnings))
+        || !(value.baseWarnings.every (warning => typeof warning === 'string')))
+      return null
+
+    const provenanceEntries = Object.entries (value.provenance)
+    if (!(hasOnlyKeys (value.attributes, ATTRIBUTE_KEYS)))
+      return null
+    if (!(Object.values (value.attributes).every (entry =>
+        typeof entry === 'string' || typeof entry === 'number')))
+      return null
+    if (!(hasOnlyKeys (value.provenance, PROVENANCE_KEYS)))
+      return null
+    if (!(provenanceEntries.every (([, origin]) => isValidOrigin (origin))))
+      return null
+
+    if (value.tagSources != null)
+      {
+        if (!(isPlainObject (value.tagSources)))
+          return null
+        if (!(hasOnlyKeys (value.tagSources, TAG_SOURCE_KEYS)))
+          return null
+        if (!(Object.values (value.tagSources).every (entry => typeof entry === 'string')))
+          return null
+      }
+
+    return {
+        sourceRow: Number (value.sourceRow),
+        url: value.url,
+        attributes: value.attributes as Record<string, string | number>,
+        fieldWarnings,
+        baseWarnings: value.baseWarnings,
+        validationErrors,
+        importErrors,
+        provenance: value.provenance as Record<string, PostImportOrigin>,
+        tagSources: value.tagSources as Record<PostImportOrigin, string> | undefined,
+        status: value.status,
+        skipReason: value.skipReason ?? undefined,
+        existingPostId:
+            isPositiveInteger (value.existingPostId) ? Number (value.existingPostId) : undefined,
+        existingPost: sanitiseExistingPost (value.existingPost),
+        metadataUrl: typeof value.metadataUrl === 'string' ? value.metadataUrl : undefined,
+        resetSnapshot,
+        createdPostId:
+            isPositiveInteger (value.createdPostId) ? Number (value.createdPostId) : undefined,
+        importStatus: value.importStatus ?? undefined,
+        recoverable: value.recoverable === true ? true : undefined }
+}
+
+const sanitiseSession = (value: unknown): PostImportSession | null => {
+    if (!(isPlainObject (value)))
+      return null
+    if (!(hasOnlyKeys (value, SESSION_KEYS)))
+      return null
+    if (value.version !== SESSION_VERSION || !(Array.isArray (value.rows)))
+      return null
+    if (value.rows.length === 0 || value.rows.length > MAX_SESSION_ROWS)
+      return null
+    if (typeof value.expiresAt !== 'string' || isExpiredSession (value.expiresAt))
+      return null
+    if (typeof value.source !== 'string' || byteLength (value.source) > MAX_SOURCE_BYTES)
+      return null
+
+    const rows = value.rows.map (sanitiseRow)
+    if (rows.some (row => row == null))
+      return null
+    if ((new Set (rows.map (row => row?.sourceRow))).size !== rows.length)
+      return null
+
+    return {
+        version: SESSION_VERSION,
+        expiresAt: value.expiresAt,
+        source: value.source,
+        rows: (rows as PostImportRow[]).map (row => recalculateThumbnailWarning (row)),
+        repairMode: value.repairMode === 'failed' ? 'failed' : 'all' }
+}
+
+
+const isExpiredSession = (expiresAt: string): boolean => {
+    const value = Date.parse (expiresAt)
+    return Number.isNaN (value) || value <= Date.now ()
+}
+
+
+export const cleanupExpiredPostImportSessions = (
+    onError?: StorageErrorHandler,
+) => {
+    if (typeof window === 'undefined')
+      return
+
+    try
+    {
+      for (let i = 0; i < sessionStorage.length; ++i)
+        {
+          const key = sessionStorage.key (i)
+          if (key == null || !(key.startsWith (SESSION_PREFIX)))
+            continue
+
+          const sessionId = validatePostImportSessionId (key.slice (SESSION_PREFIX.length))
+          if (sessionId == null)
+            {
+              sessionStorage.removeItem (key)
+              --i
+              continue
+            }
+
+          const raw = sessionStorage.getItem (key)
+          if (raw == null)
+            continue
+          if (byteLength (raw) > MAX_SESSION_JSON_BYTES)
+            {
+              sessionStorage.removeItem (key)
+              --i
+              continue
+            }
+
+          try
+          {
+            if (sanitiseSession (JSON.parse (raw)) == null)
+              {
+                sessionStorage.removeItem (key)
+                --i
+              }
+          }
+          catch
+          {
+            sessionStorage.removeItem (key)
+            --i
+          }
+        }
+    }
+    catch
+    {
+      onError?.('保存済みデータを整理できませんでした．')
+    }
 }
 
 
 export const loadPostImportSourceDraft = (
     onError?: StorageErrorHandler,
 ): { source: string } => {
-  const raw = readStorage (SOURCE_DRAFT_KEY, onError)
-  if (raw == null)
-    return { source: '' }
+    const raw = readStorage (SOURCE_DRAFT_KEY, onError)
+    if (raw == null)
+      return { source: '' }
 
-  try
-  {
-    const value = JSON.parse (raw) as { source?: string }
-    return { source: typeof value.source === 'string' ? value.source : '' }
-  }
-  catch
-  {
-    return { source: '' }
-  }
+    try
+    {
+      const value = JSON.parse (raw) as { source?: string }
+      return { source: typeof value.source === 'string' ? value.source : '' }
+    }
+    catch
+    {
+      return { source: '' }
+    }
 }
 
 
@@ -90,5 +603,73 @@ export const savePostImportSourceDraft = (
 export const clearPostImportSourceDraft = (
     onError?: StorageErrorHandler,
 ) => {
-  removeStorage (SOURCE_DRAFT_KEY, onError)
+    removeStorage (SOURCE_DRAFT_KEY, onError)
+}
+
+
+export const savePostImportSession = (
+    sessionId: string,
+    session: Omit<PostImportSession, 'version' | 'expiresAt'>,
+    onError?:  StorageErrorHandler,
+): boolean => {
+    const validatedId = validatePostImportSessionId (sessionId)
+    if (validatedId == null)
+      return false
+
+    return writeStorage (
+        sessionKey (validatedId),
+        JSON.stringify ({
+            source: session.source,
+            rows: serialisePostImportRows (session.rows),
+            repairMode: session.repairMode,
+            version: SESSION_VERSION,
+            expiresAt: new Date (Date.now () + SESSION_MAX_AGE_MS).toISOString () }),
+        onError)
+}
+
+
+export const loadPostImportSession = (
+    sessionId: string,
+    onError?: StorageErrorHandler,
+): PostImportSession | null => {
+    const validatedId = validatePostImportSessionId (sessionId)
+    if (validatedId == null)
+      return null
+
+    const raw = readStorage (sessionKey (validatedId), onError)
+    if (raw == null)
+      return null
+    if (byteLength (raw) > MAX_SESSION_JSON_BYTES)
+      {
+        removeStorage (sessionKey (validatedId), onError)
+        return null
+      }
+
+    try
+    {
+      const session = sanitiseSession (JSON.parse (raw))
+      if (session == null)
+        {
+          removeStorage (sessionKey (validatedId), onError)
+          return null
+        }
+      return session
+    }
+    catch
+    {
+      removeStorage (sessionKey (validatedId), onError)
+      return null
+    }
+}
+
+
+export const clearPostImportSession = (
+    sessionId: string,
+    onError?: StorageErrorHandler,
+) => {
+    const validatedId = validatePostImportSessionId (sessionId)
+    if (validatedId == null)
+      return
+
+    removeStorage (sessionKey (validatedId), onError)
 }

frontend/src/lib/postImportTypes.ts

@@ -1,5 +1,3 @@
-import type { Category } from '@/types'
-
 export type PostImportOrigin = 'automatic' | 'manual'
 export type PostImportRepairMode = 'all' | 'failed'
 export type PostImportStatus =
@@ -11,15 +9,9 @@ export type PostImportSkipReason = 'existing' | 'manual'
 export type PostImportResultStatus = 'created' | 'skipped' | 'failed'
 export type PostImportAttributeValue = string | number
 
-export type PostImportDisplayTag = {
-    name:            string
-    category:        Category
-    sectionLiterals?: string[] }
-
 export type PostImportResetSnapshot = {
     url:         string
     attributes:  Record<string, PostImportAttributeValue>
-    displayTags: PostImportDisplayTag[]
     provenance:  Record<string, PostImportOrigin>
     tagSources:  Record<PostImportOrigin, string>
     fieldWarnings: Record<string, string[]>
@@ -30,8 +22,7 @@ export type PostImportExistingPost = {
     id:            number
     title:         string
     url:           string
-    thumbnail?:    string | null
-    thumbnailBase?: string | null }
+    thumbnailUrl?: string }
 
 export type PostImportRow = {
     sourceRow:         number
@@ -48,7 +39,6 @@ export type PostImportRow = {
     existingPostId?:   number
     existingPost?:     PostImportExistingPost
     metadataUrl?:      string
-    displayTags?:      PostImportDisplayTag[]
     resetSnapshot:     PostImportResetSnapshot
     createdPostId?:    number
     importStatus?:     PostImportStatus
@@ -79,6 +69,13 @@ export type PostImportResultRow =
 	errors?:   Record<string, string[]>
 	recoverable?: boolean }
 
+export type PostImportSession = {
+    version:     number
+    expiresAt:   string
+    source:      string
+    rows:        PostImportRow[]
+    repairMode:  PostImportRepairMode }
+
 export type PostImportSourceIssue = {
     sourceRow: number
     message:   string

frontend/src/lib/postNewQueryState.test.ts

@@ -1,43 +0,0 @@
-import { describe, expect, it } from 'vitest'
-
-import {
-    buildPostNewReviewPath,
-    hasPostNewReviewState,
-    isPostNewReviewPathWithinLimit,
-    parsePostNewReviewUrls,
-    postNewReviewPathByteLength,
-} from '@/lib/postNewQueryState'
-
-describe ('post new review URL state', () => {
-  it ('encodes each URL separately and preserves literal plus signs', () => {
-    const urls = [
-	'https://example.com/one+a',
-	'https://example.com/two?value=b+c']
-
-    const path = buildPostNewReviewPath (urls)
-
-    expect (path).toBe (
-	'/posts/new?urls=https%3A%2F%2Fexample.com%2Fone%2Ba'
-	+ '+https%3A%2F%2Fexample.com%2Ftwo%3Fvalue%3Db%2Bc')
-    expect (parsePostNewReviewUrls (path.slice ('/posts/new'.length))).toEqual (urls)
-  })
-
-  it ('uses only the raw urls parameter as review state', () => {
-    expect (hasPostNewReviewState ('?session_id=old&meta=old')).toBe (false)
-    expect (hasPostNewReviewState ('?unknown=value&urls=')).toBe (true)
-    expect (parsePostNewReviewUrls ('?unknown=value&urls=one+two&meta=old'))
-	.toEqual (['one', 'two'])
-  })
-
-  it ('allows at most a 6 143 byte request target', () => {
-    const baseUrl = 'https://example.com/'
-    const baseLength = postNewReviewPathByteLength ([baseUrl])
-    const allowed = `${ baseUrl }${ 'a'.repeat (6_143 - baseLength) }`
-    const denied = `${ allowed }a`
-
-    expect (postNewReviewPathByteLength ([allowed])).toBe (6_143)
-    expect (isPostNewReviewPathWithinLimit ([allowed])).toBe (true)
-    expect (postNewReviewPathByteLength ([denied])).toBe (6_144)
-    expect (isPostNewReviewPathWithinLimit ([denied])).toBe (false)
-  })
-})

frontend/src/lib/postNewQueryState.ts

@@ -1,58 +1,811 @@
-const POST_NEW_REVIEW_PATH_PREFIX = '/posts/new?urls='
-const MAX_POST_NEW_REVIEW_TARGET_BYTES = 6_144
+import { resultRepairMode } from '@/lib/postImportRows'
+import { validatePostImportSessionId } from '@/lib/postImportStorage'
+
+import type {
+    PostImportOrigin,
+    PostImportRepairMode,
+    PostImportRow,
+    PostImportSkipReason,
+} from '@/lib/postImportTypes'
+
+type QueryRowState = {
+  source_row:              number
+  title:                   string
+  thumbnail_base:          string
+  original_created_from:   string
+  original_created_before: string
+  video_ms:                string
+  duration:                string
+  tags:                    string
+  parent_post_ids:         string
+  manual:                  string[]
+  skip:                    PostImportSkipReason | null
+  existing_post_id:        number | null
+  import_status:           PostImportRow['importStatus'] | null
+  created_post_id:         number | null
+  recoverable:             boolean | null }
+
+type FullRowState = QueryRowState & { url: string }
+
+type MultiRowMetaState = {
+  v:    1
+  rows: EncodedRowState[] }
+
+type EncodedSkip = 'e' | 'm'
+type EncodedImportStatus = 'p' | 'c' | 's' | 'f'
+
+type EncodedRowState = {
+  n?: number
+  u?: string
+  t?: string
+  h?: string
+  f?: string
+  b?: string
+  x?: string
+  d?: string
+  g?: string
+  p?: string
+  m?: string[]
+  s?: EncodedSkip
+  e?: number
+  i?: EncodedImportStatus
+  c?: number
+  r?: boolean }
+
+type EncodedState = {
+  v:    1
+  rows: EncodedRowState[] }
+
+export type ParsedPostNewState = {
+  rows:       PostImportRow[]
+  source:     string
+  repairMode: PostImportRepairMode
+  shortcut:   boolean }
+
+export type SerialisedPostNewState = {
+  path:     string
+  complete: boolean }
+
+const BASIC_KEYS = [
+    'url',
+    'title',
+    'thumbnail_base',
+    'original_created_from',
+    'original_created_before',
+    'video_ms',
+    'duration',
+    'tags',
+    'parent_post_ids'] as const
+const STATE_KEYS = [
+    'manual',
+    'skip',
+    'existing_post_id',
+    'import_status',
+    'created_post_id',
+    'recoverable'] as const
+const SINGLE_ROW_KEYS = [...BASIC_KEYS, ...STATE_KEYS, 'session_id'] as const
+const ENCODED_ROW_KEYS = [
+    'n',
+    'u',
+    't',
+    'h',
+    'f',
+    'b',
+    'x',
+    'd',
+    'g',
+    'p',
+    'm',
+    's',
+    'e',
+    'i',
+    'c',
+    'r'] as const
+const ALLOWED_MANUAL_FIELDS = [
+    'title',
+    'thumbnailBase',
+    'originalCreatedFrom',
+    'originalCreatedBefore',
+    'duration',
+    'tags',
+    'parentPostIds'] as const
+const MAX_REGULAR_URL_LENGTH = 768
+const MAX_COMPRESSED_STATE_LENGTH = 767
+const COMPRESSED_STATE_PREFIX = 'z1.'
+const MAX_COMPRESSED_STATE_PARAM_LENGTH = 8_192
+const MAX_COMPRESSED_STATE_BYTES = 16_384
+const MAX_DECOMPRESSED_STATE_BYTES = 262_144
+const MAX_STATE_ROWS = 100
+const MAX_QUERY_STRING_BYTES = 20_480
 
 const textEncoder = new TextEncoder ()
+const textDecoder = new TextDecoder ()
+
+const isPlainObject = (value: unknown): value is Record<string, unknown> =>
+    typeof value === 'object' && value != null && !(Array.isArray (value))
+
+const hasOnlyKeys = (
+    value:        Record<string, unknown>,
+    allowedKeys:  readonly string[],
+): boolean =>
+    Object.keys (value).every (key => allowedKeys.includes (key))
+
+const byteLength = (value: string): number =>
+    textEncoder.encode (value).byteLength
+
+const isValidSkipReason = (value: unknown): value is PostImportSkipReason =>
+    value === 'existing' || value === 'manual'
 
 
-const rawUrlsParam = (search: string): string | null => {
-  const query = search.startsWith ('?') ? search.slice (1) : search
-  if (query === '')
+const isValidImportStatus = (
+    value: unknown,
+): value is PostImportRow['importStatus'] =>
+    value === 'pending'
+    || value === 'created'
+    || value === 'skipped'
+    || value === 'failed'
+
+
+const encodeSkip = (
+    value: PostImportSkipReason | null,
+): EncodedSkip | undefined =>
+    value === 'existing'
+    ? 'e'
+    : value === 'manual'
+      ? 'm'
+      : undefined
+
+
+const decodeSkip = (
+    value: unknown,
+): PostImportSkipReason | null => {
+  if (value == null)
+    return null
+  if (value === 'e')
+    return 'existing'
+  if (value === 'm')
+    return 'manual'
+  return null
+}
+
+
+const encodeImportStatus = (
+    value: PostImportRow['importStatus'] | null,
+): EncodedImportStatus | undefined =>
+    value === 'pending'
+    ? 'p'
+    : value === 'created'
+      ? 'c'
+      : value === 'skipped'
+        ? 's'
+        : value === 'failed'
+          ? 'f'
+          : undefined
+
+
+const decodeImportStatus = (
+    value: unknown,
+): PostImportRow['importStatus'] | null => {
+  if (value == null)
+    return null
+  if (value === 'p')
+    return 'pending'
+  if (value === 'c')
+    return 'created'
+  if (value === 's')
+    return 'skipped'
+  if (value === 'f')
+    return 'failed'
+  return null
+}
+
+
+const parsePositiveInt = (value: string | null): number | null => {
+  if (value == null || value === '')
     return null
 
-  for (const segment of query.split ('&'))
+  const parsed = Number.parseInt (value, 10)
+  return Number.isInteger (parsed) && parsed > 0 ? parsed : null
+}
+
+
+const decodeBase64UrlBytes = (value: string): Uint8Array | null => {
+  try
+  {
+    const padded = value.replaceAll ('-', '+').replaceAll ('_', '/')
+    const remainder = padded.length % 4
+    const base64 =
+        remainder === 0
+        ? padded
+        : `${ padded }${ '='.repeat (4 - remainder) }`
+    const binary = window.atob (base64)
+    return Uint8Array.from (binary, char => char.charCodeAt (0))
+  }
+  catch
+  {
+    return null
+  }
+}
+
+
+const encodeBase64UrlBytes = (value: Uint8Array): string => {
+  const binary = Array.from (value, byte => String.fromCharCode (byte)).join ('')
+  return window.btoa (binary).replaceAll ('+', '-').replaceAll ('/', '_').replaceAll ('=', '')
+}
+
+
+const compressBytes = async (value: Uint8Array): Promise<Uint8Array> => {
+  const stream =
+      new Blob ([value]).stream ().pipeThrough (new CompressionStream ('gzip'))
+  return new Uint8Array (await new Response (stream).arrayBuffer ())
+}
+
+
+const decompressBytes = async (value: Uint8Array): Promise<Uint8Array> => {
+  const stream =
+      new Blob ([value]).stream ().pipeThrough (new DecompressionStream ('gzip'))
+  const bytes = new Uint8Array (await new Response (stream).arrayBuffer ())
+  if (bytes.byteLength > MAX_DECOMPRESSED_STATE_BYTES)
+    throw new Error ('decompressed state too large')
+  return bytes
+}
+
+
+const decodeCompressedState = async (value: string): Promise<string | null> => {
+  if (!(value.startsWith (COMPRESSED_STATE_PREFIX)))
+    return null
+  if (value.length > MAX_COMPRESSED_STATE_PARAM_LENGTH)
+    return null
+
+  const encoded = value.slice (COMPRESSED_STATE_PREFIX.length)
+  const compressed = decodeBase64UrlBytes (encoded)
+  if (compressed == null)
+    return null
+  if (compressed.byteLength > MAX_COMPRESSED_STATE_BYTES)
+    return null
+
+  try
+  {
+    return textDecoder.decode (await decompressBytes (compressed))
+  }
+  catch
+  {
+    return null
+  }
+}
+
+
+const encodeCompressedState = async (value: string): Promise<string> => {
+  const compressed = await compressBytes (textEncoder.encode (value))
+  return `${ COMPRESSED_STATE_PREFIX }${ encodeBase64UrlBytes (compressed) }`
+}
+
+
+const manualFields = (row: PostImportRow): string[] =>
+    ['title',
+     'thumbnailBase',
+     'originalCreatedFrom',
+     'originalCreatedBefore',
+     'duration',
+     'tags',
+     'parentPostIds']
+    .filter (field => row.provenance[field] === 'manual')
+
+
+const baseRowState = (row: PostImportRow): QueryRowState => ({
+    source_row: row.sourceRow,
+    title: String (row.attributes.title ?? ''),
+    thumbnail_base: String (row.attributes.thumbnailBase ?? ''),
+    original_created_from: String (row.attributes.originalCreatedFrom ?? ''),
+    original_created_before: String (row.attributes.originalCreatedBefore ?? ''),
+    video_ms: String (row.attributes.videoMs ?? ''),
+    duration: String (row.attributes.duration ?? ''),
+    tags: String (row.attributes.tags ?? ''),
+    parent_post_ids: String (row.attributes.parentPostIds ?? ''),
+    manual: manualFields (row),
+    skip: row.skipReason ?? null,
+    existing_post_id: row.existingPostId ?? null,
+    import_status: row.importStatus ?? null,
+    created_post_id: row.createdPostId ?? null,
+    recoverable: row.recoverable ?? null })
+
+
+const buildRow = (state: FullRowState): PostImportRow => {
+  const manual = new Set (state.manual)
+  const provenance: Record<string, PostImportOrigin> = {
+      url: 'manual',
+      title: manual.has ('title') ? 'manual' : 'automatic',
+      thumbnailBase: manual.has ('thumbnailBase') ? 'manual' : 'automatic',
+      originalCreatedFrom: manual.has ('originalCreatedFrom') ? 'manual' : 'automatic',
+      originalCreatedBefore: manual.has ('originalCreatedBefore') ? 'manual' : 'automatic',
+      videoMs: manual.has ('duration') ? 'manual' : 'automatic',
+      duration: manual.has ('duration') ? 'manual' : 'automatic',
+      tags: manual.has ('tags') ? 'manual' : 'automatic',
+      parentPostIds: manual.has ('parentPostIds') ? 'manual' : 'automatic' }
+  const tagSources = provenance.tags === 'manual'
+      ? { automatic: '', manual: state.tags }
+      : { automatic: state.tags, manual: '' }
+  const attributes = {
+      title: state.title,
+      thumbnailBase: state.thumbnail_base,
+      originalCreatedFrom: state.original_created_from,
+      originalCreatedBefore: state.original_created_before,
+      videoMs: manual.has ('duration') ? '' : state.video_ms,
+      duration: state.duration,
+      tags: state.tags,
+      parentPostIds: state.parent_post_ids }
+
+  return {
+      sourceRow: state.source_row,
+      url: state.url,
+      attributes,
+      fieldWarnings: { },
+      baseWarnings: [],
+      validationErrors: { },
+      provenance,
+      tagSources,
+      status: 'pending',
+      skipReason: state.skip ?? undefined,
+      existingPostId: state.existing_post_id ?? undefined,
+      resetSnapshot: {
+	  url: state.url,
+	  attributes: { ...attributes },
+	  provenance: { ...provenance },
+	  tagSources: { ...tagSources },
+	  fieldWarnings: { },
+	  baseWarnings: [] },
+      createdPostId: state.created_post_id ?? undefined,
+      importStatus: state.import_status ?? undefined,
+      recoverable: state.recoverable ?? undefined }
+}
+
+
+const parseManual = (value: string | null): string[] =>
+    (value ?? '')
+    .split (',')
+    .map (entry => entry.trim ())
+    .filter (entry => entry !== '')
+
+
+const hasOnlyAllowedManualFields = (value: string[]): boolean =>
+    value.every (field => ALLOWED_MANUAL_FIELDS.includes (field as never))
+
+
+const isStringArray = (value: unknown): value is string[] =>
+    Array.isArray (value) && value.every (entry => typeof entry === 'string')
+
+
+const parseEncodedRow = (
+    value:      unknown,
+    requireUrl: boolean,
+): FullRowState | null => {
+  if (!(isPlainObject (value)))
+    return null
+
+  const row = value as Record<string, unknown>
+  if (!(hasOnlyKeys (row, ENCODED_ROW_KEYS)))
+    return null
+  const url = row['u']
+  const manual = row['m']
+  const skip = decodeSkip (row['s'])
+  const importStatus = decodeImportStatus (row['i'])
+  const existingPostId = row['e']
+  const createdPostId = row['c']
+  const recoverable = row['r']
+  const sourceRow = row['n']
+
+  if (requireUrl && typeof url !== 'string')
+    return null
+  if (typeof url === 'string' && byteLength (url) > MAX_QUERY_STRING_BYTES)
+    return null
+  if (manual != null && !(isStringArray (manual)))
+    return null
+  if ((manual ?? []).some (field => !(ALLOWED_MANUAL_FIELDS.includes (field as never))))
+    return null
+  if (row['s'] != null && skip == null)
+    return null
+  if (row['i'] != null && importStatus == null)
+    return null
+  if (existingPostId != null
+      && !(typeof existingPostId === 'number'
+           && Number.isInteger (existingPostId)
+           && existingPostId > 0))
+    return null
+  if (createdPostId != null
+      && !(typeof createdPostId === 'number'
+           && Number.isInteger (createdPostId)
+           && createdPostId > 0))
+    return null
+  if (recoverable != null && typeof recoverable !== 'boolean')
+    return null
+  if (sourceRow != null
+      && !(typeof sourceRow === 'number'
+           && Number.isInteger (sourceRow)
+           && sourceRow > 0))
+    return null
+
+  const stringFields = [
+      ['t', 'title'],
+      ['h', 'thumbnail_base'],
+      ['f', 'original_created_from'],
+      ['b', 'original_created_before'],
+      ['x', 'video_ms'],
+      ['d', 'duration'],
+      ['g', 'tags'],
+      ['p', 'parent_post_ids']] as const
+  let parsedStrings: Record<(typeof stringFields)[number][1], string>
+  try
+  {
+    parsedStrings = Object.fromEntries (
+	stringFields.map (([key, target]) => {
+	  const fieldValue = row[key]
+	  if (fieldValue != null && typeof fieldValue !== 'string')
+	    throw new Error ('invalid row')
+	  if (typeof fieldValue === 'string' && byteLength (fieldValue) > MAX_QUERY_STRING_BYTES)
+	    throw new Error ('invalid row')
+	  return [target, fieldValue ?? '']
+	}),
+    ) as Record<(typeof stringFields)[number][1], string>
+  }
+  catch
+  {
+    return null
+  }
+
+  return {
+      source_row:
+          typeof sourceRow === 'number'
+          ? sourceRow
+          : 1,
+      url: typeof url === 'string' ? url : '',
+      title: parsedStrings.title,
+      thumbnail_base: parsedStrings.thumbnail_base,
+      original_created_from: parsedStrings.original_created_from,
+      original_created_before: parsedStrings.original_created_before,
+      video_ms: parsedStrings.video_ms,
+      duration: parsedStrings.duration,
+      tags: parsedStrings.tags,
+      parent_post_ids: parsedStrings.parent_post_ids,
+      manual: manual ?? [],
+      skip,
+      existing_post_id: existingPostId ?? null,
+      import_status: importStatus,
+      created_post_id: createdPostId ?? null,
+      recoverable: recoverable ?? null }
+}
+
+
+const parseSingleRow = (params: URLSearchParams): ParsedPostNewState | null => {
+  const url = params.get ('url')
+  if (url == null || url === '')
+    return null
+  if (byteLength (url) > MAX_QUERY_STRING_BYTES)
+    return null
+
+  const hasOnlyUrl = Array.from (params.keys ()).every (
+      key => key === 'url' || key === 'session_id')
+  if (hasOnlyUrl)
     {
-      if (segment === 'urls')
-        return ''
-      if (segment.startsWith ('urls='))
-        return segment.slice ('urls='.length)
+      const row = buildRow ({
+	  source_row: 1,
+	  url,
+	  title: '',
+	  thumbnail_base: '',
+	  original_created_from: '',
+	  original_created_before: '',
+	  video_ms: '',
+	  duration: '',
+	  tags: '',
+	  parent_post_ids: '',
+	  manual: [],
+	  skip: null,
+	  existing_post_id: null,
+	  import_status: null,
+	  created_post_id: null,
+	  recoverable: null })
+      return {
+	  rows: [row],
+	  source: url,
+	  repairMode: 'all',
+	  shortcut: true }
     }
 
+  if (!(Array.from (params.keys ()).every (key => SINGLE_ROW_KEYS.includes (key as never))))
+    return null
+
+  const skipValue = params.get ('skip')
+  const importStatus = params.get ('import_status')
+  const recoverable =
+      params.get ('recoverable') == null
+      ? null
+      : params.get ('recoverable') === 'true'
+  if (skipValue != null && !(isValidSkipReason (skipValue)))
+    return null
+  if (importStatus != null && !(isValidImportStatus (importStatus)))
+    return null
+  if (!(hasOnlyAllowedManualFields (parseManual (params.get ('manual')))))
+    return null
+
+  const row = buildRow ({
+      source_row: 1,
+      url,
+      title: params.get ('title') ?? '',
+      thumbnail_base: params.get ('thumbnail_base') ?? '',
+      original_created_from: params.get ('original_created_from') ?? '',
+      original_created_before: params.get ('original_created_before') ?? '',
+      video_ms: params.get ('video_ms') ?? '',
+      duration: params.get ('duration') ?? '',
+      tags: params.get ('tags') ?? '',
+      parent_post_ids: params.get ('parent_post_ids') ?? '',
+      manual: parseManual (params.get ('manual')),
+      skip: skipValue,
+      existing_post_id: parsePositiveInt (params.get ('existing_post_id')),
+      import_status: importStatus,
+      created_post_id: parsePositiveInt (params.get ('created_post_id')),
+      recoverable })
+
+  return {
+      rows: [row],
+      source: url,
+      repairMode: resultRepairMode ([row]),
+      shortcut: false }
+}
+
+
+const parseMetaRows = (
+    urlsValue: string,
+    metaValue: string,
+): ParsedPostNewState | null => {
+  const decodedBytes = decodeBase64UrlBytes (metaValue)
+  if (decodedBytes == null)
+    return null
+
+  let parsed: MultiRowMetaState
+  try
+  {
+    parsed = JSON.parse (textDecoder.decode (decodedBytes)) as MultiRowMetaState
+  }
+  catch
+  {
+    return null
+  }
+
+  if (parsed.v !== 1 || !(Array.isArray (parsed.rows)))
+    return null
+
+  const urls = urlsValue.split (' ').filter (url => url !== '')
+  if (urls.length < 2
+      || urls.length > MAX_STATE_ROWS
+      || urls.length !== parsed.rows.length
+      || parsed.rows.length > MAX_STATE_ROWS)
+    return null
+  if (urls.some (url => byteLength (url) > MAX_QUERY_STRING_BYTES))
+    return null
+
+  const fullRows = parsed.rows.map ((row, index) => {
+    const parsedRow = parseEncodedRow (row, false)
+    return parsedRow == null
+        ? null
+        : { ...parsedRow, url: urls[index] ?? '' }
+  })
+  if (fullRows.some (row => row == null))
+    return null
+  if ((new Set (fullRows.map (row => (row as FullRowState).source_row))).size !== fullRows.length)
+    return null
+
+  const rows = fullRows.map (row => buildRow (row as FullRowState))
+  return {
+      rows,
+      source: urls.join ('\n'),
+      repairMode: resultRepairMode (rows),
+      shortcut: false }
+}
+
+
+const parseFullState = async (stateValue: string): Promise<ParsedPostNewState | null> => {
+  const decoded = await decodeCompressedState (stateValue)
+  if (decoded == null)
+    return null
+
+  let parsed: EncodedState
+  try
+  {
+    parsed = JSON.parse (decoded) as EncodedState
+  }
+  catch
+  {
+    return null
+  }
+
+  if (parsed.v !== 1
+      || !(Array.isArray (parsed.rows))
+      || parsed.rows.length === 0
+      || parsed.rows.length > MAX_STATE_ROWS)
+    return null
+
+  const fullRows = parsed.rows.map (row => parseEncodedRow (row, true))
+  if (fullRows.some (row => row == null))
+    return null
+  if ((new Set (fullRows.map (row => (row as FullRowState).source_row))).size !== fullRows.length)
+    return null
+
+  const rows = fullRows.map (row => buildRow (row as FullRowState))
+  return {
+      rows,
+      source: rows.map (row => row.url).join ('\n'),
+      repairMode: resultRepairMode (rows),
+      shortcut: false }
+}
+
+
+const regularQuery = (rows: PostImportRow[]): URLSearchParams => {
+  if (rows.length === 1)
+    {
+      const row = rows[0]
+      const params = new URLSearchParams ()
+      params.set ('url', row?.url ?? '')
+      params.set ('title', String (row?.attributes.title ?? ''))
+      params.set ('thumbnail_base', String (row?.attributes.thumbnailBase ?? ''))
+      params.set ('original_created_from', String (row?.attributes.originalCreatedFrom ?? ''))
+      params.set ('original_created_before', String (row?.attributes.originalCreatedBefore ?? ''))
+      params.set ('video_ms', String (row?.attributes.videoMs ?? ''))
+      params.set ('duration', String (row?.attributes.duration ?? ''))
+      params.set ('tags', String (row?.attributes.tags ?? ''))
+      params.set ('parent_post_ids', String (row?.attributes.parentPostIds ?? ''))
+      const manual = manualFields (row).join (',')
+      if (manual !== '')
+	params.set ('manual', manual)
+      if (row.skipReason != null)
+	params.set ('skip', row.skipReason)
+      if (row.existingPostId != null)
+	params.set ('existing_post_id', String (row.existingPostId))
+      if (row.importStatus != null)
+	params.set ('import_status', row.importStatus)
+      if (row.createdPostId != null)
+	params.set ('created_post_id', String (row.createdPostId))
+      if (row.recoverable != null)
+	params.set ('recoverable', row.recoverable ? 'true' : 'false')
+      return params
+    }
+
+  const params = new URLSearchParams ()
+  params.set ('urls', rows.map (row => row.url).join (' '))
+  params.set ('meta', encodeBase64UrlBytes (textEncoder.encode (JSON.stringify ({
+      v: 1,
+      rows: rows.map (row => encodeRowState (row, false)) }))))
+  return params
+}
+
+
+const encodeRowState = (
+    row:          PostImportRow,
+    includeUrl:   boolean,
+): EncodedRowState => {
+  const base = baseRowState (row)
+  const encoded: EncodedRowState = includeUrl ? { u: row.url } : { }
+
+  encoded.n = base.source_row
+  if (base.title !== '')
+    encoded.t = base.title
+  if (base.thumbnail_base !== '')
+    encoded.h = base.thumbnail_base
+  if (base.original_created_from !== '')
+    encoded.f = base.original_created_from
+  if (base.original_created_before !== '')
+    encoded.b = base.original_created_before
+  if (base.video_ms !== '')
+    encoded.x = base.video_ms
+  if (base.duration !== '')
+    encoded.d = base.duration
+  if (base.tags !== '')
+    encoded.g = base.tags
+  if (base.parent_post_ids !== '')
+    encoded.p = base.parent_post_ids
+  if (base.manual.length > 0)
+    encoded.m = [...base.manual]
+  if (base.skip != null)
+    encoded.s = encodeSkip (base.skip)
+  if (base.existing_post_id != null)
+    encoded.e = base.existing_post_id
+  if (base.import_status != null)
+    encoded.i = encodeImportStatus (base.import_status)
+  if (base.created_post_id != null)
+    encoded.c = base.created_post_id
+  if (base.recoverable != null)
+    encoded.r = base.recoverable
+
+  return encoded
+}
+
+
+const encodeStateRows = (rows: PostImportRow[]): EncodedState => ({
+    v: 1,
+    rows: rows.map (row => encodeRowState (row, true)) })
+
+
+export const hasPostNewReviewState = (search: string): boolean => {
+  const params = new URLSearchParams (search)
+  return params.has ('state')
+      || params.has ('urls')
+      || params.has ('meta')
+      || params.has ('url')
+      || parsePostNewSessionId (search) != null
+}
+
+
+export const parsePostNewSessionId = (search: string): string | null =>
+    validatePostImportSessionId (
+        new URLSearchParams (search).get ('session_id'))
+
+
+export const appendPostNewSessionId = (
+    path:       string,
+    sessionId:  string,
+): string => {
+  const validatedId = validatePostImportSessionId (sessionId)
+  if (validatedId == null)
+    return path
+
+  const separator = path.includes ('?') ? '&' : '?'
+  return `${ path }${ separator }session_id=${ validatedId }`
+}
+
+
+export const parsePostNewState = async (
+    search: string,
+): Promise<ParsedPostNewState | null> => {
+  const params = new URLSearchParams (search)
+  const stateValue = params.get ('state')
+  if (stateValue != null)
+    return await parseFullState (stateValue)
+
+  const urlsValue = params.get ('urls')
+  const metaValue = params.get ('meta')
+  if (urlsValue != null || metaValue != null)
+    {
+      if (urlsValue == null || metaValue == null)
+	return null
+      return parseMetaRows (urlsValue, metaValue)
+    }
+
+  return parseSingleRow (params)
+}
+
+
+const serialiseCompressedRows = async (
+    rows: PostImportRow[],
+): Promise<SerialisedPostNewState | null> => {
+  try
+  {
+    for (let count = rows.length; count > 0; --count)
+      {
+	const nextRows = rows.slice (0, count)
+	const encoded = encodeStateRows (nextRows)
+	const state = await encodeCompressedState (JSON.stringify (encoded))
+	const path = `/posts/new?state=${ state }`
+	if (path.length <= MAX_COMPRESSED_STATE_LENGTH)
+	  return {
+	      path,
+	      complete: count === rows.length }
+      }
+  }
+  catch
+  {
+  }
+
   return null
 }
 
 
-export const buildPostNewReviewPath = (urls: string[]): string =>
-    `${ POST_NEW_REVIEW_PATH_PREFIX }${ urls.map (url => encodeURIComponent (url)).join ('+') }`
+export const serialisePostNewState = async (
+    rows: PostImportRow[],
+): Promise<SerialisedPostNewState | null> => {
+  const regular = regularQuery (rows).toString ()
+  const regularPath = `/posts/new?${ regular }`
+  if (regularPath.length < MAX_REGULAR_URL_LENGTH)
+    return {
+	path: regularPath,
+	complete: true }
 
-
-export const postNewReviewPathByteLength = (urls: string[]): number =>
-    textEncoder.encode (buildPostNewReviewPath (urls)).byteLength
-
-
-export const isPostNewReviewPathWithinLimit = (urls: string[]): boolean =>
-    postNewReviewPathByteLength (urls) < MAX_POST_NEW_REVIEW_TARGET_BYTES
-
-
-export const parsePostNewReviewUrls = (search: string): string[] => {
-  const raw = rawUrlsParam (search)
-  if (raw == null)
-    return []
-
-  return raw
-      .split ('+')
-      .filter (segment => segment !== '')
-      .map (segment => {
-        try
-        {
-          return decodeURIComponent (segment)
-        }
-        catch
-        {
-          return segment
-        }
-      })
+  return await serialiseCompressedRows (rows)
 }
-
-
-export const hasPostNewReviewState = (search: string): boolean =>
-    rawUrlsParam (search) != null

frontend/src/lib/useKeyboardShortcuts.tsx

@@ -25,6 +25,7 @@ import {
     getEffectiveKeyBindings,
     setClientKeyboardSettings,
 } from '@/lib/settings'
+import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
 
 import type {
     KeyBinding,
@@ -96,6 +97,7 @@ const focusSearchTarget = (): void => {
 export const KeyboardShortcutsProvider = ({ children }: PropsWithChildren) => {
   const location = useLocation ()
   const navigate = useNavigate ()
+  const { confirmDiscardNavigation } = useUnsavedChangesGuard ()
 
   const [keyboardSettings, setKeyboardSettingsState] =
       useState<ClientKeyboardSettings> (() => getClientKeyboardSettings ())
@@ -147,8 +149,11 @@ export const KeyboardShortcutsProvider = ({ children }: PropsWithChildren) => {
   }, [])
 
   const guardedNavigate = useCallback ((path: string) => {
-    navigate (path)
-  }, [navigate])
+    confirmDiscardNavigation ().then (confirmed => {
+      if (confirmed)
+	navigate (path)
+    })
+  }, [confirmDiscardNavigation, navigate])
 
   const builtinHandlers = useMemo<ShortcutHandlers> (
       () => ({

frontend/src/lib/useUnsavedChangesGuard.test.tsx

@@ -1,77 +0,0 @@
-import { fireEvent, screen, waitFor, within } from '@testing-library/react'
-import { useState } from 'react'
-import { useLocation, useNavigate } from 'react-router-dom'
-import { describe, expect, it, vi } from 'vitest'
-
-import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
-import { renderWithProviders } from '@/test/render'
-
-const GuardHarness = () => {
-  const [dirty, setDirty] = useState (true)
-  const location = useLocation ()
-  const navigate = useNavigate ()
-  const discard = vi.fn (() => setDirty (false))
-  const { allowNextNavigation } = useUnsavedChangesGuard ({
-    dirty,
-    onDiscard: discard })
-
-  return (
-      <>
-	<output aria-label="location">{location.pathname}{location.search}</output>
-	<button type="button" onClick={() => navigate ('/next?tab=one')}>move</button>
-	<button
-	    type="button"
-	    onClick={() => {
-	      allowNextNavigation ()
-	      navigate ('/allowed')
-	    }}>
-	  allowed move
-	</button>
-      </>)
-}
-
-describe ('useUnsavedChangesGuard', () => {
-  it ('blocks route changes and resets a cancelled transition', async () => {
-    renderWithProviders (<GuardHarness/>, { route: '/current' })
-
-    fireEvent.click (screen.getByRole ('button', { name: 'move' }))
-
-    expect (within (await screen.findByRole ('dialog')).getByText (
-	'変更が破棄してページ移動しますか?')).toBeInTheDocument ()
-    expect (screen.getByLabelText ('location')).toHaveTextContent ('/current')
-
-    fireEvent.click (screen.getByRole ('button', { name: '取消' }))
-
-    await waitFor (() => {
-      expect (screen.queryByRole ('dialog')).not.toBeInTheDocument ()
-    })
-    expect (screen.getByLabelText ('location')).toHaveTextContent ('/current')
-  })
-
-  it ('proceeds with the blocked transition after discard is confirmed', async () => {
-    renderWithProviders (<GuardHarness/>, { route: '/current' })
-
-    fireEvent.click (screen.getByRole ('button', { name: 'move' }))
-    fireEvent.click (await screen.findByRole ('button', {
-      name: '変更を破棄して移動' }))
-
-    await waitFor (() => {
-      expect (screen.getByLabelText ('location')).toHaveTextContent ('/next?tab=one')
-    })
-  })
-
-  it ('allows only the next navigation without leaving a bypass token', async () => {
-    renderWithProviders (<GuardHarness/>, { route: '/current' })
-
-    fireEvent.click (screen.getByRole ('button', { name: 'allowed move' }))
-    await waitFor (() => {
-      expect (screen.getByLabelText ('location')).toHaveTextContent ('/allowed')
-    })
-
-    fireEvent.click (screen.getByRole ('button', { name: 'move' }))
-
-    expect (within (await screen.findByRole ('dialog')).getByText (
-	'変更が破棄してページ移動しますか?')).toBeInTheDocument ()
-    expect (screen.getByLabelText ('location')).toHaveTextContent ('/allowed')
-  })
-})

frontend/src/lib/useUnsavedChangesGuard.tsx

@@ -1,15 +1,6 @@
-import {
-    createContext,
-    useCallback,
-    useContext,
-    useEffect,
-    useMemo,
-    useRef,
-    useState,
-} from 'react'
-import { useBlocker } from 'react-router-dom'
+import { createContext, useCallback, useContext, useMemo, useState } from 'react'
 
-import { useDialogue } from '@/lib/dialogues/useDialogue'
+import { useDialogue } from '@/components/dialogues/DialogueProvider'
 
 import type { FC, PropsWithChildren } from 'react'
 
@@ -17,16 +8,12 @@ type UnsavedChangesSource = {
     dirty:    boolean
     discard:  () => void | Promise<void> }
 
-type UseUnsavedChangesGuardOptions = {
-    dirty:      boolean
-    onDiscard?: () => void | Promise<void> }
-
 type UnsavedChangesGuardContextValue = {
-    hasUnsavedChanges:            boolean
-    registerUnsavedChangesSource: (
-        source: UnsavedChangesSource,
-    ) => () => void
-    allowNextNavigation:          () => void }
+    hasUnsavedChanges:             boolean
+    registerUnsavedChangesSource:  (
+	source: UnsavedChangesSource | null,
+    ) => void
+    confirmDiscardNavigation:      () => Promise<boolean> }
 
 const UnsavedChangesGuardContext =
     createContext<UnsavedChangesGuardContextValue | null> (null)
@@ -34,171 +21,49 @@ const UnsavedChangesGuardContext =
 
 export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children }) => {
   const dialogue = useDialogue ()
-  const sourcesRef = useRef (new Map<symbol, UnsavedChangesSource> ())
-  const bypassNextNavigationRef = useRef<symbol | null> (null)
-  const [revision, setRevision] = useState (0)
-  const dialogueOpenRef = useRef (false)
-  const handlingBlockedTransitionRef = useRef (false)
+  const [source, setSource] = useState<UnsavedChangesSource | null> (null)
 
   const registerUnsavedChangesSource = useCallback ((
-      source: UnsavedChangesSource,
-  ): (() => void) => {
-    const sourceId = Symbol ('unsaved-changes-source')
-    sourcesRef.current.set (sourceId, source)
-    setRevision (current => current + 1)
-
-    return () => {
-      if (!(sourcesRef.current.delete (sourceId)))
-        return
-
-      setRevision (current => current + 1)
-    }
+      nextSource: UnsavedChangesSource | null,
+  ) => {
+    setSource (nextSource)
   }, [])
 
-  const allowNextNavigation = useCallback (() => {
-    const token = Symbol ('allowed-navigation')
-    bypassNextNavigationRef.current = token
-
-    queueMicrotask (() => {
-      if (bypassNextNavigationRef.current === token)
-        bypassNextNavigationRef.current = null
-    })
-  }, [])
-
-  const sources = useMemo (
-      () => [...sourcesRef.current.values ()],
-      [revision],
-  )
-  const dirtySources = useMemo (
-      () => sources.filter (source => source.dirty),
-      [sources],
-  )
-  const hasUnsavedChanges = dirtySources.length > 0
-  const hasUnsavedChangesRef = useRef (hasUnsavedChanges)
-  hasUnsavedChangesRef.current = hasUnsavedChanges
-  const shouldBlock = useCallback (() => {
-    if (bypassNextNavigationRef.current != null)
-      {
-        bypassNextNavigationRef.current = null
-        return false
-      }
-
-    return hasUnsavedChangesRef.current
-  }, [])
-  const blocker = useBlocker (shouldBlock)
-
-  const confirmDiscardChanges = useCallback (async (): Promise<boolean> => {
-    if (!(hasUnsavedChanges))
+  const confirmDiscardNavigation = useCallback (async (): Promise<boolean> => {
+    if (!(source?.dirty))
       return true
 
-    if (dialogueOpenRef.current)
+    const confirmed = await dialogue.confirm ({
+	title: '未保存の変更があります',
+	description: 'このまま移動すると、保存していない変更は失われます。',
+	cancelText: 'このページに残る',
+	confirmText: '変更を破棄して移動',
+	variant: 'danger' })
+    if (!(confirmed))
       return false
 
-    dialogueOpenRef.current = true
-
-    try
-    {
-      const confirmed = await dialogue.confirm ({
-          title: '変更が破棄してページ移動しますか?',
-          confirmText: '変更を破棄して移動',
-          variant: 'danger' })
-      if (!(confirmed))
-        return false
-
-      return true
-    }
-    finally
-    {
-      dialogueOpenRef.current = false
-    }
-  }, [dialogue, hasUnsavedChanges])
-
-  useEffect (() => {
-    if (blocker.state !== 'blocked' || handlingBlockedTransitionRef.current)
-      return
-
-    handlingBlockedTransitionRef.current = true
-    void (async () => {
-      try
-      {
-        const confirmed = await confirmDiscardChanges ()
-        if (!(confirmed))
-          {
-            blocker.reset ()
-            return
-          }
-
-        let discardResults: Array<void | Promise<void>>
-        try
-        {
-	  discardResults = dirtySources.map (source => source.discard ())
-        }
-        catch
-        {
-	  blocker.reset ()
-	  return
-        }
-
-        blocker.proceed ()
-        await Promise.allSettled (discardResults)
-      }
-      finally
-      {
-        handlingBlockedTransitionRef.current = false
-      }
-    }) ()
-  }, [blocker, confirmDiscardChanges, dirtySources])
-
-  useEffect (() => {
-    if (!(hasUnsavedChanges))
-      return
-
-    const handleBeforeUnload = (event: BeforeUnloadEvent) => {
-      event.preventDefault ()
-      event.returnValue = ''
-    }
-
-    window.addEventListener ('beforeunload', handleBeforeUnload)
-    return () => {
-      window.removeEventListener ('beforeunload', handleBeforeUnload)
-    }
-  }, [hasUnsavedChanges])
+    await source.discard ()
+    return true
+  }, [dialogue, source])
 
   const value = useMemo<UnsavedChangesGuardContextValue> (() => ({
-      hasUnsavedChanges,
+      hasUnsavedChanges: source?.dirty === true,
       registerUnsavedChangesSource,
-      allowNextNavigation,
-  }), [
-      allowNextNavigation,
-      hasUnsavedChanges,
-      registerUnsavedChangesSource,
-  ])
+      confirmDiscardNavigation,
+  }), [confirmDiscardNavigation, registerUnsavedChangesSource, source?.dirty])
 
   return (
       <UnsavedChangesGuardContext.Provider value={value}>
-        {children}
+	{children}
       </UnsavedChangesGuardContext.Provider>)
 }
 
 
-export const useUnsavedChangesGuard = (
-    options?: UseUnsavedChangesGuardOptions,
-): UnsavedChangesGuardContextValue => {
+export const useUnsavedChangesGuard = (): UnsavedChangesGuardContextValue => {
   const context = useContext (UnsavedChangesGuardContext)
 
   if (context == null)
     throw new Error ('UnsavedChangesGuardProvider が必要です．')
 
-  const { registerUnsavedChangesSource } = context
-
-  useEffect (() => {
-    if (options == null)
-      return
-
-    return registerUnsavedChangesSource ({
-        dirty: options.dirty,
-        discard: options.onDiscard ?? (() => undefined) })
-  }, [options?.dirty, options?.onDiscard, registerUnsavedChangesSource])
-
   return context
 }

frontend/src/pages/materials/MaterialListPage.tsx

@@ -13,7 +13,7 @@ import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
 import { fetchMaterials, parseMaterialFilter } from '@/lib/materials'
 import { materialsKeys } from '@/lib/queryKeys'
-import { cn, dateString, inputClass } from '@/lib/utils'
+import { dateString, inputClass } from '@/lib/utils'
 
 import type { FC, FormEvent } from 'react'
 
@@ -113,11 +113,10 @@ const clearedTagSelectionPath = (
 
 const MaterialThumb: FC<{ material: Material }> = ({ material }) => (
     <div
-	className={cn (
-	    'flex aspect-square h-[180px] w-[180px] items-center justify-center',
-	    'overflow-hidden rounded-lg border border-stone-200 bg-white text-center',
-	    'text-stone-900 shadow-sm dark:border-stone-700 dark:bg-stone-900',
-	    'dark:text-stone-100')}>
+	className={`flex aspect-square h-[180px] w-[180px] items-center justify-center
+		    overflow-hidden rounded-lg border border-stone-200 bg-white text-center
+		    text-stone-900 shadow-sm dark:border-stone-700 dark:bg-stone-900
+		    dark:text-stone-100`}>
       {material.thumbnail
        ? <img src={material.thumbnail} alt="" className="block h-full w-full object-cover"/>
        : (
@@ -532,32 +531,30 @@ const MaterialListPage: FC = () => {
 
 	  <div className="flex flex-wrap items-center justify-between gap-3">
 	    <div className="flex flex-wrap gap-2">
-		      <button
-			  type="button"
-			  onClick={() => updateQuery ({ view: 'card' })}
-			  className={cn (
-			      'rounded-full border px-4 py-2 text-sm',
-			      view === 'card'
-			      ? [
-				  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
-				  'dark:bg-sky-950 dark:text-sky-100']
-			      : [
-				  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
-				  'dark:bg-stone-900 dark:text-stone-100'])}>
+	      <button
+		  type="button"
+		  onClick={() => updateQuery ({ view: 'card' })}
+		  className={`rounded-full border px-4 py-2 text-sm ${
+		      view === 'card'
+		      ? [
+			  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
+			  'dark:bg-sky-950 dark:text-sky-100'].join (' ')
+		      : [
+			  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
+			  'dark:bg-stone-900 dark:text-stone-100'].join (' ') }`}>
 		アイコン
 	      </button>
-		      <button
-			  type="button"
-			  onClick={() => updateQuery ({ view: 'list' })}
-			  className={cn (
-			      'rounded-full border px-4 py-2 text-sm',
-			      view === 'list'
-			      ? [
-				  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
-				  'dark:bg-sky-950 dark:text-sky-100']
-			      : [
-				  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
-				  'dark:bg-stone-900 dark:text-stone-100'])}>
+	      <button
+		  type="button"
+		  onClick={() => updateQuery ({ view: 'list' })}
+		  className={`rounded-full border px-4 py-2 text-sm ${
+		      view === 'list'
+		      ? [
+			  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
+			  'dark:bg-sky-950 dark:text-sky-100'].join (' ')
+		      : [
+			  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
+			  'dark:bg-stone-900 dark:text-stone-100'].join (' ') }`}>
 		詳細
 	      </button>
 	    </div>

frontend/src/pages/posts/PostImportResultPage.test.tsx

@@ -0,0 +1,48 @@
+import { render, screen } from '@testing-library/react'
+import { MemoryRouter, Navigate, Route, Routes } from 'react-router-dom'
+import { describe, expect, it } from 'vitest'
+
+describe ('legacy post import routes', () => {
+  it ('redirects /posts/import to /posts/new', () => {
+    render (
+        <MemoryRouter initialEntries={['/posts/import']}>
+          <Routes>
+            <Route path="/posts/import" element={<Navigate to="/posts/new" replace/>}/>
+            <Route path="/posts/new" element={<div>SOURCE ROUTE</div>}/>
+          </Routes>
+        </MemoryRouter>)
+
+    expect (screen.getByText ('SOURCE ROUTE')).toBeInTheDocument ()
+  })
+
+  it ('redirects legacy review routes to /posts/new', () => {
+    render (
+        <MemoryRouter initialEntries={['/posts/import/legacy/review']}>
+          <Routes>
+            <Route
+                path="/posts/import/:sessionId/review"
+                element={<Navigate to="/posts/new" replace/>}/>
+            <Route path="/posts/new" element={<div>SOURCE ROUTE</div>}/>
+          </Routes>
+        </MemoryRouter>)
+
+    expect (screen.getByText ('SOURCE ROUTE')).toBeInTheDocument ()
+  })
+
+  it ('redirects legacy result routes to /posts', () => {
+    render (
+        <MemoryRouter initialEntries={['/posts/import/legacy/result']}>
+          <Routes>
+            <Route
+                path="/posts/import/:sessionId/result"
+                element={<Navigate to="/posts" replace/>}/>
+            <Route
+                path="/posts/new/:sessionId/result"
+                element={<Navigate to="/posts" replace/>}/>
+            <Route path="/posts" element={<div>POSTS ROUTE</div>}/>
+          </Routes>
+        </MemoryRouter>)
+
+    expect (screen.getByText ('POSTS ROUTE')).toBeInTheDocument ()
+  })
+})

frontend/src/pages/posts/PostImportReviewPage.test.tsx

@@ -1,157 +1,448 @@
-import { fireEvent, screen, waitFor } from '@testing-library/react'
-import { useLocation } from 'react-router-dom'
+import { fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { HelmetProvider } from 'react-helmet-async'
+import { MemoryRouter, Route, Routes } from 'react-router-dom'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
+import { loadPostImportSession, savePostImportSession } from '@/lib/postImportSession'
 import PostImportReviewPage from '@/pages/posts/PostImportReviewPage'
 import { buildUser } from '@/test/factories'
-import { renderWithProviders } from '@/test/render'
+import { buildPostImportRow } from '@/test/postImportFactories'
 
-import type { ReactNode } from 'react'
+import type { DialogueFormAction, DialogueFormControls } from '@/lib/dialogues/useDialogue'
+import type { PostImportRow } from '@/lib/postImportSession'
 
 const api = vi.hoisted (() => ({
   apiGet: vi.fn (),
   apiPost: vi.fn (),
-  isApiError: vi.fn (() => false) }))
+}))
+
+const toastApi = vi.hoisted (() => ({
+  toast: vi.fn (),
+}))
+
+const dialogue = vi.hoisted (() => ({
+  form: vi.fn (() => Promise.resolve ()),
+}))
 
 vi.mock ('@/lib/api', () => api)
-vi.mock ('framer-motion', () => ({
-  AnimatePresence: ({ children }: { children?: ReactNode }) => <>{children}</>,
-  motion: {
-    div: ({ children }: { children?: ReactNode }) => <div>{children}</div>,
-    main: ({ children }: { children?: ReactNode }) => <main>{children}</main> } }))
+vi.mock ('@/components/ui/use-toast', () => toastApi)
+vi.mock ('@/lib/dialogues/useDialogue', () => ({
+  default: () => dialogue,
+}))
 
-const metadata = (url: string, title: string) => ({
-  url,
-  title,
-  thumbnailBase: 'https://example.com/thumbnail.jpg',
-  originalCreatedFrom: '',
-  originalCreatedBefore: '',
-  duration: '',
-  tags: '',
-  parentPostIds: [],
-  fieldWarnings: { },
-  baseWarnings: [],
-  displayTags: [] })
-
-
-const LocationProbe = () => {
-  const location = useLocation ()
-  return <output aria-label="current-location">{location.pathname}{location.search}</output>
-}
-
-
-const renderReviewPage = (urls: string[]) => {
-  const search = urls.map (url => encodeURIComponent (url)).join ('+')
-  return renderWithProviders (
-      <>
-	<PostImportReviewPage user={buildUser ()}/>
-	<LocationProbe/>
-      </>,
-      { route: `/posts/new?urls=${ search }` })
-}
+const renderReviewPage = (route = '/posts/new/review') =>
+  render (
+      <HelmetProvider>
+        <MemoryRouter initialEntries={[route]}>
+          <Routes>
+            <Route path="/posts/new" element={<div>SOURCE ROUTE</div>}/>
+            <Route
+                path="/posts/new/review"
+                element={<PostImportReviewPage user={buildUser ()}/>}/>
+            <Route path="/posts" element={<div>POSTS ROUTE</div>}/>
+          </Routes>
+        </MemoryRouter>
+      </HelmetProvider>)
 
 describe ('PostImportReviewPage', () => {
   beforeEach (() => {
+    sessionStorage.clear ()
     vi.clearAllMocks ()
-    api.isApiError.mockReturnValue (false)
+    globalThis.URL.createObjectURL = vi.fn (() => 'blob:preview')
+    globalThis.URL.revokeObjectURL = vi.fn ()
+    api.apiGet.mockResolvedValue (new Blob (['img'], { type: 'image/png' }))
   })
 
-  it ('fetches metadata with at most four concurrent requests', async () => {
-    const resolvers: Array<(value: ReturnType<typeof metadata>) => void> = []
-    api.apiGet.mockImplementation ((_path, options) =>
-	new Promise (resolve => {
-	  resolvers.push (resolve)
-	  const url = String (options.params.url)
-	  void url
-	}))
-    const urls = Array.from (
-	{ length: 6 },
-	(_, index) => `https://example.com/${ index + 1 }`)
-
-    renderReviewPage (urls)
-
-    await waitFor (() => expect (api.apiGet).toHaveBeenCalledTimes (4))
-
-    resolvers[0]?.(metadata (urls[0]!, 'first'))
-
-    expect (await screen.findAllByText ('first')).toHaveLength (2)
-    await waitFor (() => expect (api.apiGet).toHaveBeenCalledTimes (5))
-    expect (screen.getByRole ('button', { name: '追加' })).toBeDisabled ()
-
-    for (let index = 1; index < resolvers.length; ++index)
-      resolvers[index]?.(metadata (urls[index]!, `post ${ index + 1 }`))
-  })
-
-  it ('keeps successful rows when another metadata request fails', async () => {
-    api.apiGet
-	.mockResolvedValueOnce (metadata ('https://example.com/one', 'first'))
-	.mockRejectedValueOnce (new TypeError ('network'))
-
-    renderReviewPage (['https://example.com/one', 'https://example.com/two'])
-
-    expect (await screen.findAllByText ('first')).toHaveLength (2)
-    await waitFor (() => {
-      expect (screen.getAllByText ('登録不可')).toHaveLength (2)
-    })
-    expect (screen.getAllByRole ('button', { name: '編輯' })[0]).toBeEnabled ()
-  })
-
-  it ('shows existing posts with Active Storage thumbnail precedence', async () => {
-    api.apiGet.mockResolvedValue ({
-      ...metadata ('https://example.com/post', ''),
-      existingPostId: 24,
-      existingPost: {
-	id: 24,
-	title: 'existing post',
-	url: 'https://example.com/post',
-	thumbnail: 'https://example.com/storage.jpg',
-	thumbnailBase: 'https://example.com/base.jpg' } })
-
-    renderReviewPage (['https://example.com/post'])
-
-    const disclosure = await screen.findByRole ('button', {
-      name: '既存投稿による自動スキップ 1件' })
-    expect (screen.getByRole ('button', { name: '追加' })).toBeDisabled ()
-
-    fireEvent.click (disclosure)
-
-    expect ((await screen.findAllByRole ('img', { name: 'サムネール' }))[0])
-	.toHaveAttribute ('src', 'https://example.com/storage.jpg')
-  })
-
-  it ('keeps a recoverable bulk failure on the review screen', async () => {
-    api.apiGet.mockResolvedValue (
-	metadata ('https://example.com/post', 'new post'))
-    api.apiPost.mockResolvedValue ({
-      results: [{
-	status: 'failed',
-	recoverable: true,
-	errors: { title: ['invalid title'] } }] })
-
-    renderReviewPage (['https://example.com/post'])
-
-    fireEvent.click (await screen.findByRole ('button', { name: '追加' }))
-
-    expect (await screen.findAllByText ('登録失敗')).toHaveLength (2)
-    expect (screen.getAllByText ('invalid title')).toHaveLength (2)
-    expect (screen.getAllByRole ('button', { name: '編輯' })[0]).toBeEnabled ()
-    expect (screen.getAllByRole ('button', { name: '再試行' })[0]).toBeEnabled ()
-    expect (screen.getByLabelText ('current-location')).toHaveTextContent ('/posts/new?')
-  })
-
-  it ('navigates to /posts after every submitted row is created', async () => {
-    api.apiGet.mockResolvedValue (
-	metadata ('https://example.com/post', 'new post'))
-    api.apiPost.mockResolvedValue ({
-      results: [{ status: 'created', post: { id: 42 } }] })
-
-    renderReviewPage (['https://example.com/post'])
-
-    fireEvent.click (await screen.findByRole ('button', { name: '追加' }))
+  it ('redirects to /posts/new when no current work exists', async () => {
+    renderReviewPage ()
 
     await waitFor (() => {
-      expect (screen.getByLabelText ('current-location')).toHaveTextContent ('/posts')
+      expect (screen.getByText ('SOURCE ROUTE')).toBeInTheDocument ()
     })
-    expect (api.apiPost).toHaveBeenCalledWith ('/posts/bulk', expect.any (FormData))
+  })
+
+  it ('restores the current work on review reload', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({
+        sourceRow: 1,
+        attributes: { title: 'restored row' } })] })
+
+    renderReviewPage ()
+
+    expect (screen.getByRole ('heading', { name: '追加内容確認' })).toBeInTheDocument ()
+    expect (screen.queryByText ('広場に投稿を追加')).not.toBeInTheDocument ()
+    expect (screen.queryByText ('投稿インポート')).not.toBeInTheDocument ()
+    expect (await screen.findByText ('restored row')).toBeInTheDocument ()
+  })
+
+  it ('does not expose メタデータ to the user', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({
+        sourceRow: 1,
+        fieldWarnings: { title: ['自動取得に失敗しました．'] } })] })
+
+    renderReviewPage ()
+
+    expect (screen.queryByText (/メタデータ/)).not.toBeInTheDocument ()
+  })
+
+  it ('returns to /posts/new while keeping the current work', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({
+        sourceRow: 1,
+        attributes: { title: 'restored row' } })] })
+
+    renderReviewPage ()
+
+    fireEvent.click (await screen.findByRole ('button', { name: 'URL リスト入力へ戻る' }))
+
+    await waitFor (() => {
+      expect (screen.getByText ('SOURCE ROUTE')).toBeInTheDocument ()
+    })
+    expect (loadPostImportSession ()?.rows[0]?.attributes.title).toBe ('restored row')
+  })
+
+  it ('disables row editing and navigation while batch import is running', async () => {
+    let resolveValidation: ((value: { rows: PostImportRow[] }) => void) | null = null
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({ sourceRow: 1 })] })
+    api.apiPost.mockImplementationOnce (() =>
+        new Promise<{ rows: PostImportRow[] }> (resolve => {
+          resolveValidation = resolve
+        }))
+    api.apiPost.mockResolvedValueOnce ({
+      created: 0,
+      skipped: 0,
+      failed: 0,
+      rows: [] })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+
+    await waitFor (() => {
+      expect (screen.getByRole ('button', { name: '編輯' })).toBeDisabled ()
+      expect (screen.getByRole ('button', { name: 'URL リスト入力へ戻る' })).toBeDisabled ()
+      expect (screen.getByRole ('button', { name: '取込実行' })).toBeDisabled ()
+    })
+
+    resolveValidation?.({ rows: [buildPostImportRow ({ sourceRow: 1 })] })
+  })
+
+  it ('does not call import when validation omits a requested source row', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post-1\nhttps://example.com/post-2',
+      repairMode: 'all',
+      rows: [
+        buildPostImportRow ({ sourceRow: 1 }),
+        buildPostImportRow ({ sourceRow: 2 })] })
+    api.apiPost.mockResolvedValueOnce ({
+      rows: [buildPostImportRow ({ sourceRow: 1 })] })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+
+    await waitFor (() => {
+      expect (toastApi.toast).toHaveBeenCalledWith (
+          expect.objectContaining ({ title: '再検証結果が不完全でした' }))
+    })
+    expect (api.apiPost).toHaveBeenCalledTimes (1)
+  })
+
+  it ('navigates to /posts when all rows finish as created or skipped', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({ sourceRow: 1 })] })
+    api.apiPost
+        .mockResolvedValueOnce ({
+          rows: [buildPostImportRow ({ sourceRow: 1 })] })
+        .mockResolvedValueOnce ({
+          created: 1,
+          skipped: 0,
+          failed: 0,
+          rows: [{
+            sourceRow: 1,
+            status: 'created',
+            post: { id: 1 } }] })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+
+    await waitFor (() => {
+      expect (screen.getByText ('POSTS ROUTE')).toBeInTheDocument ()
+    })
+    expect (loadPostImportSession ()).toBeNull ()
+  })
+
+  it ('stays on review when a recoverable failed row remains', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({ sourceRow: 1 })] })
+    api.apiPost
+        .mockResolvedValueOnce ({
+          rows: [buildPostImportRow ({ sourceRow: 1 })] })
+        .mockResolvedValueOnce ({
+          created: 0,
+          skipped: 0,
+          failed: 1,
+          rows: [{
+            sourceRow: 1,
+            status: 'failed',
+            recoverable: true,
+            errors: { title: ['invalid'] } }] })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+
+    expect (await screen.findByText ('invalid')).toBeInTheDocument ()
+    expect (screen.queryByText ('POSTS ROUTE')).not.toBeInTheDocument ()
+  })
+
+  it ('keeps edited recoverable rows in session before the next batch submit', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'failed',
+      rows: [buildPostImportRow ({
+        sourceRow: 1,
+        attributes: { title: 'old title', duration: '2' },
+        importStatus: 'failed',
+        recoverable: true,
+        importErrors: { base: ['failed'] } })] })
+    api.apiPost
+        .mockResolvedValueOnce ({
+          rows: [buildPostImportRow ({
+            sourceRow: 1,
+            attributes: { title: 'edited title', duration: '2' },
+            importStatus: 'pending',
+            recoverable: true })] })
+        .mockResolvedValueOnce ({
+          rows: [buildPostImportRow ({
+            sourceRow: 1,
+            attributes: { title: 'edited title', duration: '2' },
+            importStatus: 'pending',
+            recoverable: true })] })
+        .mockResolvedValueOnce ({
+          created: 0,
+          skipped: 0,
+          failed: 1,
+          rows: [{
+            sourceRow: 1,
+            status: 'failed',
+            recoverable: true,
+            errors: { title: ['invalid'] } }] })
+    dialogue.form.mockImplementationOnce (async options => {
+      let actions: DialogueFormAction[] = []
+      const controls: DialogueFormControls = {
+        close: vi.fn (),
+        confirm: vi.fn (),
+        setActions: next => {
+          actions = next
+        } }
+
+      render (options.body (controls))
+      await waitFor (() => expect (actions.length).toBe (2))
+      fireEvent.change (screen.getByDisplayValue ('old title'), {
+        target: { value: 'edited title' } })
+      await actions.find (action => action.label === '編輯内容を保存')?.onSelect ()
+    })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '編輯' }))
+
+    await waitFor (() => {
+      const saved = loadPostImportSession ()
+      expect (saved?.rows[0]?.attributes.title).toBe ('edited title')
+      expect (saved?.rows[0]?.importStatus).toBe ('pending')
+    })
+
+    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+
+    await waitFor (() => {
+      expect (api.apiPost.mock.calls[1]?.[1]?.rows?.[0]?.attributes?.title)
+          .toBe ('edited title')
+      expect (api.apiPost.mock.calls[1]?.[1]?.rows?.[0]?.attributes?.duration)
+          .toBe ('2')
+    })
+  })
+
+  it ('retries only failed rows and does not resend created or skipped rows', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'failed',
+      rows: [
+        buildPostImportRow ({
+          sourceRow: 1,
+          importStatus: 'created',
+          createdPostId: 1 }),
+        buildPostImportRow ({
+          sourceRow: 2,
+          importStatus: 'skipped',
+          skipReason: 'existing',
+          existingPostId: 2 }),
+        buildPostImportRow ({
+          sourceRow: 3,
+          importStatus: 'failed',
+          recoverable: true,
+          importErrors: { base: ['failed'] } })] })
+    api.apiPost
+        .mockResolvedValueOnce ({
+          rows: [buildPostImportRow ({
+            sourceRow: 3,
+            importStatus: 'pending',
+            recoverable: true })] })
+        .mockResolvedValueOnce ({
+          created: 0,
+          skipped: 1,
+          failed: 0,
+          rows: [{
+            sourceRow: 3,
+            status: 'skipped',
+            existingPostId: 9 }] })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '再試行' }))
+
+    await waitFor (() => {
+      expect (api.apiPost.mock.calls[1]?.[1]?.rows).toEqual ([
+        expect.objectContaining ({ sourceRow: 3 })])
+    })
+  })
+
+  it ('allows ready rows to be manually skipped and excludes them from API payloads', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({ sourceRow: 1 })] })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('checkbox', { name: 'スキップ' }))
+
+    await waitFor (() => {
+      expect (screen.getByText ('POSTS ROUTE')).toBeInTheDocument ()
+    })
+    expect (api.apiPost).not.toHaveBeenCalled ()
+  })
+
+  it ('restores values and errors when manual skip is cleared', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [buildPostImportRow ({
+        sourceRow: 1,
+        status: 'error',
+        attributes: { title: 'kept title' },
+        validationErrors: { title: ['invalid'] } })] })
+
+    renderReviewPage ()
+
+    const toggle = await screen.findByRole ('checkbox', { name: 'スキップ' })
+    fireEvent.click (toggle)
+    fireEvent.click (screen.getByRole ('checkbox', { name: 'スキップ' }))
+
+    expect (screen.getByText ('kept title')).toBeInTheDocument ()
+    expect (screen.getByText ('invalid')).toBeInTheDocument ()
+  })
+
+  it ('moves existing skipped rows into the collapsed section', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'all',
+      rows: [
+        buildPostImportRow ({
+          sourceRow: 1,
+          attributes: { title: 'existing row' },
+          skipReason: 'existing',
+          existingPostId: 2 }),
+        buildPostImportRow ({
+          sourceRow: 2,
+          attributes: { title: 'normal row' } })] })
+
+    renderReviewPage ()
+
+    expect (screen.getByText ('既存投稿による自動スキップ 1件')).toBeInTheDocument ()
+    expect (screen.queryByText ('existing row')).not.toBeInTheDocument ()
+    expect (screen.getByText ('normal row')).toBeInTheDocument ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '既存投稿による自動スキップ 1件' }))
+
+    expect (screen.getByText ('existing row')).toBeInTheDocument ()
+    expect (screen.queryAllByRole ('button', { name: '編輯' })).toHaveLength (1)
+    expect (screen.queryAllByRole ('checkbox', { name: 'スキップ' })).toHaveLength (1)
+  })
+
+  it ('navigates to /posts when the last failed row completes', async () => {
+    savePostImportSession ({
+      source: 'https://example.com/post',
+      repairMode: 'failed',
+      rows: [
+        buildPostImportRow ({
+          sourceRow: 1,
+          importStatus: 'created',
+          createdPostId: 1 }),
+        buildPostImportRow ({
+          sourceRow: 2,
+          importStatus: 'failed',
+          recoverable: true,
+          importErrors: { base: ['failed'] } })] })
+    api.apiPost
+        .mockResolvedValueOnce ({
+          rows: [buildPostImportRow ({
+            sourceRow: 2,
+            importStatus: 'pending',
+            recoverable: true })] })
+        .mockResolvedValueOnce ({
+          created: 1,
+          skipped: 0,
+          failed: 0,
+          rows: [{
+            sourceRow: 2,
+            status: 'created',
+            post: { id: 2 } }] })
+
+    renderReviewPage ()
+
+    fireEvent.click (screen.getByRole ('button', { name: '再試行' }))
+
+    await waitFor (() => {
+      expect (screen.getByText ('POSTS ROUTE')).toBeInTheDocument ()
+    })
+  })
+
+  it ('sorts recoverable pending validation rows to the top in repair mode', () => {
+    savePostImportSession ({
+      source: '',
+      repairMode: 'failed',
+      rows: [
+        buildPostImportRow ({
+          sourceRow: 2,
+          attributes: { title: 'normal row' } }),
+        buildPostImportRow ({
+          sourceRow: 1,
+          attributes: { title: 'repair row' },
+          importStatus: 'pending',
+          recoverable: true,
+          validationErrors: { title: ['invalid'] } })] })
+
+    const { container } = renderReviewPage ()
+
+    const titles = Array.from (container.querySelectorAll ('.line-clamp-2')).map (
+        node => node.textContent)
+    expect (titles[0]).toBe ('repair row')
   })
 })

frontend/src/pages/posts/PostImportSourcePage.test.tsx

@@ -1,12 +1,21 @@
-import { fireEvent, screen } from '@testing-library/react'
+import { fireEvent, screen, waitFor } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import PostImportSourcePage from '@/pages/posts/PostImportSourcePage'
 import { buildUser } from '@/test/factories'
+import { buildPostImportRow } from '@/test/postImportFactories'
 import { renderWithProviders } from '@/test/render'
 
+const api = vi.hoisted (() => ({
+  apiPost: vi.fn (),
+  isApiError: vi.fn () }))
+
 const router = vi.hoisted (() => ({ navigate: vi.fn () }))
 
+const toastApi = vi.hoisted (() => ({ toast: vi.fn () }))
+
+vi.mock ('@/lib/api', () => api)
+vi.mock ('@/components/ui/use-toast', () => toastApi)
 vi.mock ('react-router-dom', async importOriginal => ({
   ...await importOriginal<typeof import('react-router-dom')> (),
   useNavigate: () => router.navigate }))
@@ -15,53 +24,71 @@ describe ('PostImportSourcePage', () => {
   beforeEach (() => {
     sessionStorage.clear ()
     vi.clearAllMocks ()
+    api.isApiError.mockReturnValue (false)
   })
 
-  it ('validates an empty source only after Next is pressed', () => {
+  it ('shows no empty error initially and validates only after Next is pressed', () => {
     renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
 
+    expect (screen.getByRole ('heading', { name: '広場に投稿を追加' })).toBeInTheDocument ()
+    expect (screen.queryByText ('投稿インポート')).not.toBeInTheDocument ()
     expect (screen.queryByText ('URL を入力してください．')).not.toBeInTheDocument ()
-
     fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
-
     expect (screen.getByText ('URL を入力してください．')).toBeInTheDocument ()
-    expect (router.navigate).not.toHaveBeenCalled ()
+    expect (api.apiPost).not.toHaveBeenCalled ()
   })
 
-  it ('reports frontend URL issues with original line numbers', () => {
+  it ('shows frontend URL issues with line numbers without requesting preview', () => {
     renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
     const input = screen.getByRole ('textbox', { name: '' })
 
     fireEvent.change (input, {
       target: { value: '\nftp://example.com/file\nhttps://example.com/valid' } })
+    expect (screen.queryByText (/2 行目/)).not.toBeInTheDocument ()
     fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
 
     expect (screen.getByText (/2 行目: HTTP または HTTPS/)).toBeInTheDocument ()
     expect (screen.getByText ('ftp://example.com/file')).toBeInTheDocument ()
     expect (input).toHaveAttribute ('aria-invalid', 'true')
-    expect (router.navigate).not.toHaveBeenCalled ()
+    expect (input.getAttribute ('aria-describedby')).toContain ('post-import-source-issues')
+    expect (api.apiPost).not.toHaveBeenCalled ()
   })
 
-  it ('navigates with individually encoded URLs without calling an API', () => {
+  it ('shows backend URL errors against original input without a session', async () => {
+    api.apiPost.mockResolvedValue ({
+      rows: [buildPostImportRow ({
+	sourceRow: 2,
+	url: 'https://example.com/canonical',
+	status: 'error',
+	validationErrors: { url: ['URL が重複しています．'] } })] })
     renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
 
     fireEvent.change (screen.getByRole ('textbox', { name: '' }), {
-      target: {
-	value: 'https://example.com/one+a\nhttps://example.com/two?value=b+c' } })
+      target: { value: '\nhttps://example.com/original' } })
     fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
 
-    expect (router.navigate).toHaveBeenCalledWith (
-	'/posts/new?urls=https%3A%2F%2Fexample.com%2Fone%2Ba'
-	+ '+https%3A%2F%2Fexample.com%2Ftwo%3Fvalue%3Db%2Bc')
+    expect (await screen.findByText ('2 行目: URL が重複しています．')).toBeInTheDocument ()
+    expect (screen.getAllByText ('https://example.com/original')).toHaveLength (2)
+    expect (router.navigate).not.toHaveBeenCalled ()
+    expect (Array.from ({ length: sessionStorage.length }, (_, index) =>
+	sessionStorage.key (index))).not.toContainEqual(
+	    expect.stringMatching (/^post-import-session:/))
   })
 
-  it ('disables Next when the encoded request target reaches 4096 bytes', () => {
+  it ('navigates to /posts/new with query state after a successful preview', async () => {
+    api.apiPost.mockResolvedValue ({ rows: [buildPostImportRow ()] })
     renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
-    const input = screen.getByRole ('textbox', { name: '' })
 
-    fireEvent.change (input, {
-      target: { value: `https://example.com/${ 'a'.repeat (6_200) }` } })
+    fireEvent.change (screen.getByRole ('textbox', { name: '' }), {
+      target: { value: 'https://example.com/post' } })
+    fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
 
-    expect (screen.getByRole ('button', { name: '次へ' })).toBeDisabled ()
+    await waitFor (() => {
+      expect (router.navigate).toHaveBeenCalledWith (
+          expect.stringMatching (/^\/posts\/new\?/))
+    })
+    expect (Array.from ({ length: sessionStorage.length }, (_, index) =>
+	sessionStorage.key (index))).not.toContainEqual(
+	    expect.stringMatching (/^post-import-session:/))
   })
 })

frontend/src/pages/posts/PostImportSourcePage.tsx

@@ -12,23 +12,26 @@ import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import {
-    buildPostNewReviewPath,
-    isPostNewReviewPathWithinLimit,
+    appendPostNewSessionId,
+    serialisePostNewState,
 } from '@/lib/postNewQueryState'
-import {
-    countImportSourceLines,
-    extractImportSourceUrls,
-    validateImportSource,
-} from '@/lib/postImportSourceValidation'
-import {
-    loadPostImportSourceDraft,
-    savePostImportSourceDraft,
-} from '@/lib/postImportStorage'
 import { canEditContent } from '@/lib/users'
+import { countImportSourceLines,
+	 generatePostImportSessionId,
+	 cleanupExpiredPostImportSessions,
+	 initialisePreviewRows,
+	 loadPostImportSession,
+	 loadPostImportSourceDraft,
+	 resultRepairMode,
+	 serialisedPostImportRowsEqual,
+	 savePostImportSession,
+	 savePostImportSourceDraft,
+	 validateImportSource } from '@/lib/postImportSession'
 import Forbidden from '@/pages/Forbidden'
 
 import type { FC } from 'react'
 
+import type { PostImportRow } from '@/lib/postImportSession'
 import type { User } from '@/types'
 
 type Props = { user: User | null }
@@ -37,6 +40,69 @@ const MAX_ROWS = 100
 const SOURCE_ERROR_ID = 'post-import-source-error'
 const SOURCE_ISSUES_ID = 'post-import-source-issues'
 
+const buildInitialRows = (source: string): PostImportRow[] =>
+    source
+        .split (/\r\n|\n|\r/)
+        .map ((line, index) => ({
+            sourceRow: index + 1,
+            url: line.trim () }))
+        .filter (row => row.url !== '')
+        .map (row => ({
+            sourceRow: row.sourceRow,
+            url: row.url,
+            attributes: {
+                title: '',
+                thumbnailBase: '',
+                originalCreatedFrom: '',
+                originalCreatedBefore: '',
+                duration: '',
+                videoMs: '',
+                tags: '',
+                parentPostIds: '' },
+            fieldWarnings: { },
+            baseWarnings: [],
+            validationErrors: { },
+            provenance: {
+                url: 'manual',
+                title: 'automatic',
+                thumbnailBase: 'automatic',
+                originalCreatedFrom: 'automatic',
+                originalCreatedBefore: 'automatic',
+                duration: 'automatic',
+                videoMs: 'automatic',
+                tags: 'automatic',
+                parentPostIds: 'automatic' },
+            tagSources: {
+                automatic: '',
+                manual: '' },
+            status: 'pending' as const,
+            resetSnapshot: {
+                url: row.url,
+                attributes: {
+                    title: '',
+                    thumbnailBase: '',
+                    originalCreatedFrom: '',
+                    originalCreatedBefore: '',
+                    duration: '',
+                    videoMs: '',
+                    tags: '',
+                    parentPostIds: '' },
+                provenance: {
+                    url: 'manual',
+                    title: 'automatic',
+                    thumbnailBase: 'automatic',
+                    originalCreatedFrom: 'automatic',
+                    originalCreatedBefore: 'automatic',
+                    duration: 'automatic',
+                    videoMs: 'automatic',
+                    tags: 'automatic',
+                    parentPostIds: 'automatic' },
+                tagSources: {
+                    automatic: '',
+                    manual: '' },
+                fieldWarnings: { },
+                baseWarnings: [] } }))
+
 
 const PostImportSourcePage: FC<Props> = ({ user }) => {
   const editable = canEditContent (user)
@@ -49,8 +115,6 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
   const editedRef = useRef (false)
 
   const lineCount = countImportSourceLines (source)
-  const sourceUrls = extractImportSourceUrls (source)
-  const withinPathLimit = isPostNewReviewPathWithinLimit (sourceUrls)
   const messages = sourceError != null ? [sourceError] : []
   const sourceDescribedBy =
       [sourceError != null ? SOURCE_ERROR_ID : null,
@@ -58,7 +122,13 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
       .filter (value => value != null)
       .join (' ')
 
+  const showStorageError = (message: string) =>
+      toast ({ description: message })
+
   useEffect (() => {
+    cleanupExpiredPostImportSessions (message =>
+	toast ({ title: '保存済みデータを整理できませんでした', description: message }))
+
     const draft = loadPostImportSourceDraft (message =>
 	toast ({ title: '保存済み入力を復元できませんでした', description: message }))
 
@@ -101,15 +171,73 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 	setSourceError (null)
 	return
       }
-    if (!(withinPathLimit))
-      return
 
     setLoading (true)
     setSourceIssues ([])
     setSourceError (null)
     try
     {
-      navigate (buildPostNewReviewPath (sourceUrls))
+      const nextRows = initialisePreviewRows (buildInitialRows (source))
+      const serialised = await serialisePostNewState (nextRows)
+      const sessionId = (() => {
+	try
+	{
+	  return generatePostImportSessionId ()
+	}
+	catch
+	{
+	  return null
+	}
+      }) ()
+      const session = {
+	  source,
+	  rows: nextRows,
+	  repairMode: resultRepairMode (nextRows) }
+      const saved =
+	  sessionId == null
+	  ? false
+	  : savePostImportSession (sessionId, session, showStorageError)
+      const loadedSession =
+	  sessionId == null
+	  ? null
+	  : loadPostImportSession (sessionId, showStorageError)
+      const sessionRoundTripSucceeded =
+	  saved
+	  && serialisedPostImportRowsEqual (
+	      loadedSession?.rows ?? [],
+	      nextRows)
+      const canNavigate =
+	  serialised?.complete === true
+	  || sessionRoundTripSucceeded
+      if (!(canNavigate))
+	{
+	  showStorageError ('ブラウザへ保存できませんでした．')
+	  return
+	}
+
+      const nextPath = (() => {
+	if (serialised != null)
+	  {
+	    return sessionId == null
+		? serialised.path
+		: appendPostNewSessionId (serialised.path, sessionId)
+	  }
+	if (sessionRoundTripSucceeded && sessionId != null)
+	  return `/posts/new?session_id=${ sessionId }`
+	return null
+      }) ()
+      if (nextPath == null)
+	{
+	  showStorageError ('ブラウザへ保存できませんでした．')
+	  return
+	}
+
+      navigate (nextPath)
+    }
+    catch (error)
+    {
+      console.error (error)
+      showStorageError ('ブラウザへ保存できませんでした．')
     }
     finally
     {
@@ -128,7 +256,7 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 
 	<Form className="max-w-4xl">
 	  <PageTitle>広場に投稿を追加</PageTitle>
-	  <FormField label="URL リスト（1 行 1 URL）">
+	  <FormField label="URL リスト">
 	    {() => (
 		<TextArea
 		    value={source}
@@ -138,9 +266,8 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 		    className="h-80 font-mono text-sm"
 		    onBlur={() => {
 		      savePostImportSourceDraft (source, message =>
-			  toast ({
-			      title: '入力内容を保存できませんでした',
-			      description: message }))
+			  toast ({ title: '入力内容を保存できませんでした',
+				   description: message }))
 		    }}
 		    onChange={ev => {
 		      editedRef.current = true
@@ -170,7 +297,7 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 		type="button"
 		className="pointer-events-auto shrink-0"
 		onClick={preview}
-		disabled={loading || !(withinPathLimit)}>
+		disabled={loading}>
 	      次へ
 	    </Button>
 	  </div>

frontend/src/pages/posts/PostNewPage.test.tsx

@@ -1,4 +1,5 @@
 import { screen } from '@testing-library/react'
+import { MemoryRouter, Route, Routes } from 'react-router-dom'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import PostNewPage from '@/pages/posts/PostNewPage'
@@ -6,7 +7,6 @@ import { buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
 const api = vi.hoisted (() => ({
-  apiGet: vi.fn (),
   apiPost: vi.fn (),
   isApiError: vi.fn () }))
 
@@ -16,23 +16,27 @@ describe ('PostNewPage', () => {
   beforeEach (() => {
     vi.clearAllMocks ()
     api.isApiError.mockReturnValue (false)
-    api.apiGet.mockResolvedValue ({
-      url: 'https://example.com/post',
-      title: 'post',
-      tags: '' })
     sessionStorage.clear ()
   })
 
   it ('shows the source page on /posts/new', () => {
-    renderWithProviders (<PostNewPage user={buildUser ()}/>, {
-      route: '/posts/new' })
+    renderWithProviders (
+        <MemoryRouter initialEntries={['/posts/new']}>
+          <Routes>
+            <Route path="/posts/new" element={<PostNewPage user={buildUser ()}/>}/>
+          </Routes>
+        </MemoryRouter>)
 
     expect (screen.getByRole ('heading', { name: '広場に投稿を追加' })).toBeInTheDocument ()
   })
 
   it ('shows the review page when query state is present', () => {
-    renderWithProviders (<PostNewPage user={buildUser ()}/>, {
-      route: '/posts/new?urls=https%3A%2F%2Fexample.com%2Fpost' })
+    renderWithProviders (
+        <MemoryRouter initialEntries={['/posts/new?url=https%3A%2F%2Fexample.com%2Fpost']}>
+          <Routes>
+            <Route path="/posts/new" element={<PostNewPage user={buildUser ()}/>}/>
+          </Routes>
+        </MemoryRouter>)
 
     expect (screen.getByRole ('heading', { name: '追加内容確認' })).toBeInTheDocument ()
     expect (screen.queryByText ('広場に投稿を追加')).not.toBeInTheDocument ()

frontend/src/pages/tags/NicoTagListPage.test.tsx

@@ -6,6 +6,7 @@ import { dateString } from '@/lib/utils'
 import { buildTag, buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
+import type { ReactNode } from 'react'
 import type { NicoTag } from '@/types'
 
 const api = vi.hoisted (() => ({
@@ -26,10 +27,10 @@ const scrollIntoView = vi.fn ()
 
 vi.mock ('@/lib/api', () => api)
 vi.mock ('@/components/ui/use-toast', () => toastApi)
-vi.mock ('@/components/dialogues/DialogueProvider', async importOriginal => ({
-  ...await importOriginal<
-      typeof import('@/components/dialogues/DialogueProvider')> (),
-  useDialogue: () => dialogue }))
+vi.mock ('@/components/dialogues/DialogueProvider', () => ({
+  default: ({ children }: { children: ReactNode }) => <>{children}</>,
+  useDialogue: () => dialogue,
+}))
 
 const buildNicoTag = (values: Partial<NicoTag> = {}): NicoTag => ({
     ...buildTag (),

frontend/src/pages/theatres/TheatreDetailPage.test.tsx

@@ -40,10 +40,10 @@ const postEmbed = vi.hoisted (() => ({
 
 vi.mock ('@/lib/api', () => api)
 vi.mock ('@/lib/posts', () => postsApi)
-vi.mock ('@/components/dialogues/DialogueProvider', async importOriginal => ({
-  ...await importOriginal<
-      typeof import('@/components/dialogues/DialogueProvider')> (),
-  useDialogue: () => dialogue }))
+vi.mock ('@/components/dialogues/DialogueProvider', () => ({
+  default: ({ children }: { children: ReactNode }) => <>{children}</>,
+  useDialogue: () => dialogue,
+}))
 vi.mock ('@/components/PostEmbed', () => ({
   default: (props: {
     ref?: { current: unknown }
@@ -262,9 +262,7 @@ describe ('TheatreDetailPage', () => {
     expect (postEmbed.seek).not.toHaveBeenCalledWith (0)
   })
 
-  it (
-      'shows child tags from the post tag tree in both vertical and horizontal layouts',
-      async () => {
+  it ('shows child tags from the post tag tree in both vertical and horizontal layouts', async () => {
     const childTag = buildTag ({ id: 12, name: '子タグ', category: 'general' })
     const parentTag = buildTag ({
       id:       11,
@@ -309,7 +307,7 @@ describe ('TheatreDetailPage', () => {
       expect (within (tagSection ()).getAllByRole ('link', { name: '子タグ' }))
 	.toHaveLength (1)
     })
-      })
+  })
 
   it ('does not advance host post while video length is unknown', async () => {
     api.apiPut.mockImplementation ((path: string) => {

frontend/src/pages/users/SettingPage.tsx

@@ -1197,9 +1197,13 @@ const SettingPage: FC<Props> = ({ user, setUser }) => {
   }, [hasUnsavedThemeChanges, savedThemeSlots])
 
   useEffect (() => {
-    return registerUnsavedChangesSource ({
-        dirty: hasPageUnsavedChanges,
-        discard: discardAllDirtyChanges })
+    registerUnsavedChangesSource ({
+	dirty: hasPageUnsavedChanges,
+	discard: discardAllDirtyChanges })
+
+    return () => {
+      registerUnsavedChangesSource (null)
+    }
   }, [discardAllDirtyChanges, hasPageUnsavedChanges, registerUnsavedChangesSource])
 
   useKeyboardShortcuts ({

frontend/src/test/coverage.todo.test.ts

@@ -0,0 +1,10 @@
+import { describe, it } from 'vitest'
+
+describe ('pending high-level browser coverage', () => {
+  it.todo ('adds MSW-backed API boundary tests in a follow-up issue')
+  it.todo ('covers TheatreDetailPage with timer polling, comment posting, and next-post updates')
+  it.todo ('covers NicoTagListPage linking and pagination against realistic API payloads')
+  it.todo ('covers TagDetailSidebar drag/drop parent-child editing with pointer-event fidelity')
+  it.todo ('covers TopNav desktop and mobile menu flows as browser-level integration tests')
+  it.todo ('covers full App bootstrap for user creation, user verification, and 503 handling')
+})

frontend/src/test/postImportFactories.ts

@@ -1,4 +1,4 @@
-import type { PostImportRow } from '@/lib/postImportTypes'
+import type { PostImportRow } from '@/lib/postImportSession'
 
 export const buildPostImportRow = (
     overrides: Partial<PostImportRow> = {},

frontend/src/test/render.tsx

@@ -1,8 +1,7 @@
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { render } from '@testing-library/react'
-import { createContext, useContext, useState } from 'react'
 import { HelmetProvider } from 'react-helmet-async'
-import { createMemoryRouter, RouterProvider } from 'react-router-dom'
+import { MemoryRouter } from 'react-router-dom'
 
 import DialogueProvider from '@/components/dialogues/DialogueProvider'
 import { KeyboardShortcutsProvider } from '@/lib/useKeyboardShortcuts'
@@ -14,20 +13,6 @@ type Options = {
   route?: string
 }
 
-const TestContentContext = createContext<ReactNode> (null)
-
-
-const TestRoute = () => {
-  const children = useContext (TestContentContext)
-
-  return (
-      <UnsavedChangesGuardProvider>
-        <KeyboardShortcutsProvider>
-          {children}
-        </KeyboardShortcutsProvider>
-      </UnsavedChangesGuardProvider>)
-}
-
 export const renderWithProviders = (
     ui:       ReactElement,
     options: Options = {},
@@ -37,23 +22,20 @@ export const renderWithProviders = (
       queries: { retry: false } },
   })
 
-  const Wrapper = ({ children }: { children: ReactNode }) => {
-    const [router] = useState (() => createMemoryRouter ([{
-        path: '*',
-        element: <TestRoute/> }], {
-        initialEntries: [options.route ?? '/'] }))
-
-    return (
-	<QueryClientProvider client={queryClient}>
-	  <HelmetProvider>
-	    <DialogueProvider>
-	      <TestContentContext.Provider value={children}>
-		<RouterProvider router={router}/>
-	      </TestContentContext.Provider>
-	    </DialogueProvider>
-	  </HelmetProvider>
-	</QueryClientProvider>)
-  }
+  const Wrapper = ({ children }: { children: ReactNode }) => (
+      <QueryClientProvider client={queryClient}>
+        <HelmetProvider>
+          <MemoryRouter initialEntries={[options.route ?? '/']}>
+            <DialogueProvider>
+              <UnsavedChangesGuardProvider>
+                <KeyboardShortcutsProvider>
+                  {children}
+                </KeyboardShortcutsProvider>
+              </UnsavedChangesGuardProvider>
+            </DialogueProvider>
+          </MemoryRouter>
+        </HelmetProvider>
+      </QueryClientProvider>)
 
   return {
     queryClient,